Long ago in a distant land, I, Aku, the shape shifting master of darkness, unleashed an unspeakable evil.
But a foolish samurai warrior wielding a magic sword stepped forth to oppose me.
Before the final blow was struck, I tore open a portal in time, and flung him into the future where my evil is law.
Now the fool seeks to return to the past and undo the future that is Aku.

—Aku, Original Intro for Samurai Jack and Episode CI

Aku was the main antagonist of the series Samurai Jack. Born from a cosmic black mass of darkness, Aku was an evil, shapeshifting demon that has taken over the world and ruled it for countless eons. Throughout the series, he was voiced by Mako Iwamatsu in seasons 1-4, but due to his death in 2006, he was replaced by Greg Baldwin in Season 5.

Though he was capable of shifting his form into virtually anything he wished due to his metamorphic body, his standard form after self-upgrading and adapting to the Earth was roughly a humanoid being with a black body, a green mouth, and a red beard extending from the bottom of his chin. He had six horns, four long and two short, extending from his head, and eyebrows made of red, flickering flame. In his standard form, he also tends not to have legs, with his body simply ending at the bottom with robe-like darkness that sometimes manifested as flames. He was several stories tall. A deep droning noise was often heard around him when he appears.

Aku constantly antagonized Jack, often attacking him when he was weak, and other times defending himself from Jack's own gambits. Prior to Ashi sending Jack back in time to vanquish his past self, the two seem doomed never to defeat each other, and while Jack has beaten him on numerous occasions, Aku merely transformed into a creature and retreated, usually calling out a taunt over his shoulder. He was entirely aware of his inability to defeat Jack and even lampshaded this in "Episode XLVIII: Jack versus Aku", which eventually discouraged him from fighting Jack further. Aku could be considered the deuteragonist of the series as a whole (albeit a rare, villainous one), as while Ashi becomes this in Season 5, Aku had the most focus in the narrative besides Jack.

While he's usually presented as a serious and threatening foe, Aku is also a source of comedy in the show, due to his outrageous design and sometimes wise-guy behavior, supported by Mako's over the top voice-acting.

Aku means "Evil" in Japanese. It is written as "悪" in Kanji. The kanji can also be pronounced as "Waru".



Long ago in the vastness of space, a great, formless, mindless entity of evil arose. Before it could do harm to the universe, it was set upon by the three prime deities of the Aesir, Egyptian, and Hindu mythologies: Odin the All-father, Ra the Sun God, and Vishnu, the Supreme God and Soul. The three deities fought a fierce battle against the black mass, burning the entity almost completely out of existence with their divine power. However, during the battle, one small fragment of the entity was incidentally cut from the whole by Odin and did not burn away.

Unnoticed by the three deities, this seemingly small fragment floated away from the site of the battle and drifted through space for an untold amount of time, until it eventually, and violently, crashed on Earth during the Cretaceous period of the Mesozoic era. It is implied that the fragment of the black mass was the very object that caused the extinction of the dinosaurs although the crash occurred in prehistoric Japan as opposed to the Yucatan peninsula by a massive asteroid.

Over eons, the fragment evolved into an ever-growing ominous forest of black tree-like spikes, surrounding a tar-like pit at its center that devoured any living thing that dared enter. Eventually, the forest grew so large that the Emperor (Jack's father) decided to kill the evil at its source. Armed with a poison elixir given to him by a Buddhist monk, the Emperor, and his cavalry rode into the heart of the forest. But as they rode, the forest began to gradually kill off his men, leaving the Emperor himself as the only survivor. Once he arrived at the black lake in the forest's center, the Samurai Lord doused an arrow into the elixir he was given and fired it into the black lake, believing that it would destroy the evil forest.

Unexpectedly, the poison arrow's magic had the unforeseen effect of galvanizing the evil mass into a humanoid form, giving it intelligence, sentience, and shape-shifting abilities. The evil proclaimed its name to be Aku and thanked the Emperor for inadvertently helping him. The Emperor attacked Aku, but with nothing more than his mundane, mortal weapons, he could inflict no harm upon the being. Aku easily defeated the Emperor and strapped him to the side of a tree so that he could watch as Aku began to destroy his home and slaughter his people.

However, the Deities, sensing the good in the Samurai Lord, summoned him to them with the aid of Odin's horse Sleipnir. Taking the good inside him, they used avatar bodies to create an enchanted sword that was capable of harming Aku. Armed with the sword and a magical suit of armor, the Emperor plunged into battle against Aku. In the end, the Emperor was victorious and proceeded to seal him in the devastated wasteland in the form of a jagged black tree. As he was sealed away, Aku vowed he would one day return. During the battle, the Emperor's wife gave birth to a son. Determined to learn from the catastrophe, and aware that Aku would indeed one day return, the Emperor and his family hatched a plan and orchestrated the events that would set Jack on his eventual years of training.


Eight years later, during a solar eclipse, the seal the emperor placed on Aku broke and was released. His first target was the village of the emperor who sealed him eight years prior. In a castle, Jack was a young child and his father was telling him how he defeated Aku. After the story was done, Jack was left alone, playing with a toy sword. Suddenly, the castle was covered in Aku's shadow. Aku unleashed a vicious attack on the city. Jack's father attempted to get the sword, but Aku captured him before he could reach it. The Lord told his wife it was time to enact the plan they had prepared. Following the plan, Jack's mother escaped with him and the sword. Jack then started on his journey to prepare both physically and mentally for his confrontation against Aku.

Many years later, a formidably trained Jack returned to find his land devastated and his people, including his father, enslaved and horribly suffering, forced to harvest the rich resources of their land for Aku to increase his powers and spread his evil across the entire planet. Filled with righteous wrath, Jack quickly slew Aku's minions and went to Aku's palace to slay him. After a vicious battle, Jack eventually overpowered Aku. However, before Jack could finish him off, a desperate Aku tore open a portal in time and flung him into the distant future, a future in which Aku was certain that his evil would be spread out all over the world.

The Future

Unknown millennia passed before Jack reappeared into the future. During that time, Aku managed to terrorize and subjugate the majority of the entire world, making himself the undisputed ruler of Earth. Although he began with demonic servants to carry out his will, he later became enamored with mechanical ones since his demonic servants could not carry out his tasks fast enough. Aku then recruited mad scientists to make the X-Model. All but one were eventually destroyed before the next generation of Aku's army was developed: the Beetle Drones. Successors to the X-Models, the beetle drones became the model for a series of insect-themed minions that served Aku well into the height of his power and were his standard henchmen.

Hungry for more power, Aku established the Earth as a space-faring world, opening his ports to surrounding worlds in order to plunder and conquer worlds beyond as well. The influx of aliens, ranging from enslaved species to rough immigrants, have made the Earth a hodge-podge of a dystopian society primarily run by tyrants and gangs. The few bastions of peace and hope typically remain out of Aku's wide field of vision. During Jack's revelation to Ashi, he showed her that Aku has apparently spread the word throughout the universe that criminals are welcomed on Earth, which has made it a safe haven for some of the worst scum in existence. They, in some cases, have decimated occupied settlements inhabited by innocent, helpless residents without any scruples. Corrupted agents have also made the lives of countless innocents worthless under Aku's regime. Unsavory establishments such as the Dome of Doom and Creature Combat Club are common in the world under Aku.

Aku initially had a habit of watching Jack from afar and stewing over his inability to kill him. He took any and every opportunity to destroy the samurai, whether through unleashing his minion armies, hiring bounty hunters, using power objects, clever traps, trickery and deceit, and other methods in an unending struggle.

Despite being highly feared, hated and despised by almost all sentient beings in the world and the universe, some people worship him like a divine figure. The prime example is the Cult of Aku.

During his last encounter with Jack, Aku managed to stop Jack from jumping through the last known time portal and subsequently destroyed it. He then revealed to Jack that he had destroyed all the other time portals in existence, ostensibly ending Jack's quest to return to the past which also inadvertently broke the seal Jack placed on Mad Jack. Reveling in the samurai's anger, Aku fled the scene after transforming three small goat creatures into monsters, which Jack then butchered in his rage. Immediately after this encounter with Aku, the samurai lost his magical sword but as Aku had left moments before, he did not witness this event.

50 Years in the Future

After destroying the last known time portal and eliminating Jack's ability to return to his own time, Aku decided to stop confronting Jack personally. Instead, he continued to send bounty hunters after Jack while simply waiting for him to die of old age, assuming that his victory would in this way be assured. However, it later became apparent that Jack's initial time-traveling had halted his natural aging process, eternally leaving him at the same biological age as when Aku first sent him to the future. This discovery scuttled Aku's plan and left him at somewhat of a loss as to what to do about his seemingly ageless foe. Ironically, despite Aku's fear of confronting Jack, the samurai did not manage to recover his lost sword, rendering him helpless against any potential attack by Aku. But because Aku had given up attempting to defeat Jack personally, he did not discover that Jack had lost his sword, and none of the bounty hunters who encountered Jack ever managed to report back to Aku alive. Somewhat oddly, though Aku never discovered that Jack had lost his sword, he did somehow learn that Jack had grown a beard. During this time, he also came to realize, much to his annoyance, that stories of Jack's experiences had begun to inspire relatively wide-spread rebellion against him. Frightened of encountering Jack, Aku could do little personally to stop the uprisings and fell into something of a depression. Trapped in an eternal stalemate with Jack, Aku began to develop a degree of apathy even towards his tyrannical rule. He even began seeing a therapist in a sense by splitting himself into two entities and talking to himself.

At one point long after his last encounter with Jack, his fortress was attacked by a large military force, which included an army of Scotswomen led by their father, The Scotsman. Hoping to shake himself out of his funk, Aku nonchalantly destroyed most of the army himself. After simply flattening most of his enemies by rolling over them in the form of a giant black sphere, he prepared to destroy the group of Scotswomen, who had been instructed to flee by their father. However before he could do so, he was confronted by the Scotsman. Hoping to distract Aku, the Scotsman mocked him incessantly for being scared of Jack and consequently losing much of his fearsome reputation. After enduring the Scotsman's taunts for a short time, Aku incinerated his foe with his eye-beams. However, he quickly became unhappy again due to the Scotsman mentioning Jack and returned to his fortress, forgetting to kill the Scotsman's daughters and missing the Scotsman's return as a ghost. He also later received a phone call from the severed head of the assassin Scaramouche, who had learned that Jack's sword was missing and hoped to inform Aku. However, random circumstance and Scaramouche's undiplomatic nature conspired to prevent Aku from learning of Jack's plight.

Eventually, however, Scaramouche managed to reach Aku and report the status of Jack's sword, unknown to him that the information arrived too late. After Scaramouche tells him, Aku angrily pushes down hard on Scaramouche's head, asking if he's sure. Excited with the news, an immediately reinvigorated Aku confronted Jack for the first time in decades, only to discover the samurai had already recovered his weapon. After destroying Scaramouche in anger, Aku casually attempted to leave the area until he noticed a familiar smell coming from Jack's companion, Ashi. Suddenly remembering the time he visited the Cult of Aku and offered them some of his essence, Aku quickly deduced that Ashi was his biological daughter and used the essence inside her to control her into fighting Jack, casually remarking to a giant robot corpse how his (last remaining) daughter had fallen and run off with his mortal enemy. Already bored with Jack's attempt to free her, Aku simply tossed the robot onto them before corrupting Ashi with a new bodysuit in his likeness. When Jack couldn't bring himself to kill Ashi and surrendered, Aku ordered his daughter to stand down, claiming Jack's sword for himself and relishing in his victory.


In the series finale, Aku captured Jack and stole his sword, broadcasting his victory to everyone in the world, if not the universe, once again relishing in his victory. Aku prepared to kill Jack in front of the whole universe, but was confused as to how he should kill his arch-enemy. After a period of indecision, Aku decides it's best for Ashi to kill Jack. As Ashi prepares to kill Jack, all of Jack's allies soon arrive and fight Aku and his forces in a grand-scale battle while Jack deals with the corrupted Ashi. Aku finds amusement in the armies attempts to save Jack, as while they may be able to fight off Aku's forces, Aku himself is nearly untouchable. Eventually, Ashi frees herself of Aku's corruption but retains his powers, realising this she quickly gets Jack's katana back, and before Aku can stop them she warps Jack and herself back to the past, the last time that the future Aku is seen he utters his last words of "Oh no...." with an extremely worried look on his face, knowing that his end will soon come. In the past the events of the first episode play out: Jack has just defeated and weakened Aku, who promises that he will destroy Jack in the future, and opens up a time portal and sends Jack into the future, however Aku is soon caught off guard when Jack and Ashi arrive in the same spot where he was cast in the future, ten seconds after it had happened, confusing Aku as to how Jack was 'back already', unaware that the Jack standing in front of him has spent fifty years searching for a way back to the past. Jack rushes at Aku and attacks him without mercy, quickly making short work of Aku and sealing him inside his sword again, this time, however, Jack uses his sword to destroy Aku once and for all, by plunging it with Aku still inside into the ground, causing Aku's lair to explode, taking him with it, thus preventing the rise of Aku and sparing both the universe and the future from his tyranny.


Tragically, since Ashi was Aku's daughter, she would pass away before she and Jack were wedded. The same presumably happened to every single being in the future since Aku was the catalyst for their existence in some ways. Despite that, Aku's destruction means all the evil he has inflicted was undone, thus sparing those who live in misery under his tyranny from such fate.

Ironically, it is shown that Aku still, albeit indirectly, was capable of hurting Jack emotionally when his past destruction affected Ashi's existence since she was his daughter.


Aku is evil incarnate; he embodies the very essence of an evil overlord. Cruel and domineering to all he meets, it's obey or be obliterated with Aku. Arrogant, temperamental, and sadistic by default, he has ruled the planet for thousands of years and does not take kindly to disobedience. Aku is responsible for countless genocides, with cities, towns, villages, and small settlements being completely destroyed, alongside all their inhabitants, while nature itself is left to rot or decimated to make room for Aku's strongholds. It is likely that religions are also affected, given Aku's loathing towards all that is good and sacred.

Furthermore, lack to none of the divine intervention from the gods has allowed him to conquer Earth and rule its inhabitants with iron fists. While Aku has recreated numerous lands into his own image, he is often just as satisfied with leaving entire areas barren wastelands, seeing the carnage as reminders of his power to the general populace. Atrocities are a daily occurrence since Aku's rule, as he welcomes wanted criminals from across the galaxy and provides them with areas that are still fully occupied, entrusting the new arrivals to wipe the populaces from the earth.

When faced with opposition, Aku finds enjoyment in slaughtering thousands of rebel armies with ease, and will often make one's circumstances even worse than death if they still long to fight him. Such was the case of the Lava Monster who fought against Aku, even as the villain decimated all his warriors. As punishment, Aku encased the man in a crystal and forced him to watch as he slaughtered everyone he loved and destroyed his kingdom, finally placing him within the depths of a mountain, refusing to grant him a warrior's death. A similar action was performed shortly after Aku's true birth, forcing Jack's father, the Emperor, to watch him begin his reign of terror on his homeland.

To increase his already formidable power, Aku will also plunder the world, and countless other planets of their riches and resources and enslave surrounding species to do the heavy lifting. Those that refuse are often tortured and executed, as with the case of Jack's people and the canine archaeologists. Numerous scientists are recruited, so that Aku may leverage their intelligence to create an unstoppable army of robots to take over various lands considerably quicker and eliminate more carefully hidden pockets of resistance. His powers are even able to conjure up demons and monstrosities, who are unleashed upon the land to create further sorrow and misery.

He is outright, merciless and inhumane, to say the least, but has enough of an understanding of humanity to manipulate the feelings of others, often blackmailing others to perform his will and then betray his promises to them once they fulfilled their services. Aku is as intelligent as he is powerful, and his cunning knows little end, from taking the form of a woman to trick Jack or manipulating various races into serving him. He is also dishonest and has no shame or remorse, and he routinely goes back on his word either to serve himself or simply for amusement.

Aku takes pleasure in slave labor, having enslaved countless races across the universe. These slaves are often forced to build monuments in Aku's likeness and mine precious resources. When they fail to do so, the slaves are punished terribly and sometimes executed, such in the case of the talking canines. The slaves of Aku's empire often die due to exhaustion and lack of food, only to be replaced with more slaves. Aku particularly enjoyed doing this to great and powerful people such as The Emperor, seeing it as the ultimate insult to have them live the lives of revered and respectable figures, only to spend the rest of their lives as helpless slaves later.

Despite this, he possesses a dry sense of humor and often jokes when in a good mood, mocking Jack whenever he can and however he can. For instance, in one episode Aku holds a time portal just out of Jack's reach as Jack jumps for it. He is also rather "genre savvy", and will occasionally lean on the fourth wall or lampshade either his own villainous tendencies or various cliche situations. He is also a frequent source of comic relief in the show, due, in prime, to his reactions to the things around him.

While Aku seems to have a soft spot for children at times, this seems to be most indicative of his views of seeing immense value in not simply eradicating them, but rather convincing them via various means to view him as the "hero" of the planet and not Samurai Jack, making them useful servants in the future to shape successive generations. This can be seen in Aku's Fairy Tales where he attempted to make children admire him by telling them tales that depict himself as a hero and Jack as a villain.

Unfortunately for him, the children weren't impressed hearing his increasingly ludicrous tales, causing him to vanish in rage after roaring "the end". In Jack and the Rave, he composed an evil techno music that hypnotizes children, again showcasing his lust to indoctrinate young kids into his evil ways, making them dance for him and commit crimes. In episode C, he seemingly welcomes Ashi as his own flesh and blood, and even delighted by the fact that he has daughters.

He fondly called Ashi "sweetheart" and himself as "daddy", but this choice of words could have been chosen to further upset Ashi and Jack. However, he had no qualms about manipulating his newly revealed daughter into fighting Jack while lamenting that his child fell for his sworn enemy. Despite this, Aku's many genocides of countless nations have included children as well and the villain previously targeted a young Samurai Jack shortly after the subjugation of his homeland, knowing the threat the son of his former nemesis, the Emperor, would pose to him if left unchecked.

After 50 years of battling Jack, Aku's personality seems to be largely unchanged and appear to be more mellow, though he appears to have sunk into something of a depression due to Jack's agelessness, causing Aku to stop caring about being the ruler of the world, having a more noticeably annoyed and fed up expression on his face, with his attitude reflecting this, where once before he would have killed whoever displeased him, in this state of annoyance he instead got annoyed that the muck people had dirtied the floor of his lair, telling them he 'just had it vacuumed!' and angrily told them to leave, this also extends to the robots that are sent to kill Jack, as he has stopped caring about new tech his scientists have created to battle Jack, once telling them 'And I care because?'. While he claimed at one point not to care about Jack's fate, he was actually deeply disturbed by this discovery, as long experience with Jack had demonstrated that his foe was unlikely to fall into the hands of any of Aku's minions, leaving the two of them in a potentially eternal stalemate. The idea that he and Jack would have to spend eternity fighting had gotten to him so badly he actually split himself in two and had the other half become his therapist to do check ups on his mental health.

This depression appears to have caused a degree of apathy in Aku, or at least unhappy resignation, as Aku apparently knows that the population of Earth is beginning to rebel against his rule, but is either unable or unwilling to do much about it personally due to having lost track of Jack. His depression also makes him avoid contact with others beings from outside his palace in which he makes the giant voice recorder in his likeliness that record his message said that he doesn't want to meet anyone and ask them to go away. At the same time, he also cares less about tributes.

Despite this, Aku's sadistic tendencies appear to be largely intact, as he appeared to be quite pleased with himself after incinerating the Scotsman and destroying most of the army that attacked his fortress. However, even this tendency appears to have been reduced to a considerable degree, as Aku appeared to be more nonchalant than pleased during his destruction of the rebel army. After being confronted by the Scotsman, he either completely forgot to kill the Scotsman's daughters, or simply didn't bother out of disinterest. Additionally, he was shown at one point becoming upset with a group of mud creatures who, in presenting him with tribute, dirtied a recently vacuumed floor. But instead of having the creatures killed or imprisoned as he seemed to do to others in the past on a whim, he merely shouted at them to leave.

After hearing Jack loses his sword, he nearly reverts back to his own self and happy to the point of dancing around with Scaramouche. However, after discovering Jack has regained the sword, he angrily blasts Scaramouche to oblivion. During this time, he is shown to be cautious enough not to engage Jack in battle head-on instead he relies on controlling Ashi to deal with Jack in order to toy with him as well as cunningly knowing the fact that Jack will try his best to avoid hurting Ashi. At the same time, he also loses interest in fighting Jack since he tries to leave after seeing Jack with the sword again knowing full well the result of the fight.

Although he is an absolute ruler of the world, he is not above paying bills to use services, like when he pays the phone bill to allow Scaramouche to talk to him or ordering bounty hunters to kill Jack. It is also shown he courteous enough to hold the phone to wait for service respond. Shockingly, in episode C, he was even polite enough to state his absence, not to mention an apology for any inconvenience of not be able to meet him in person, though he did end the recording by screaming at the listener to leave.

Despite being the incarnation of pure evil, he apparently never committed any form of sexual assault and even understand them, as he himself expressed surprise at Ashi's birth, showing his lack of understanding at a human's reproductive system.

Abilities and Powers

Aku was well known for being one of the most powerful characters of the series. He had a large range of powers and capabilities that made him almost unstoppable. Aku is a demonic entity which Jack has described as the personification of primordial evil, one of the most powerful beings in the series, with only a few who are capable of fighting him.

  • Near-Immortality: As a supernatural being, Aku is ageless and nearly immortal. He requires no sustenance and cannot be harmed by mortal means. Only the power of righteous spirits or divine weapons like Jack's sword, or divine entities, are capable of doing him any severe harm.
  • Shapeshifting: Aku could change into virtually any form he desired, from a giant dragon to a small insect, or even a beautiful woman. He was able to seamlessly change his size, liquefy himself, or stretch and expand his body. He could even replicate into clones of himself to be in numerous places at once, with his mind inhabiting numerous bodies. At one point, he even manifested a second version of himself to act as a psychologist; performing talk-therapy on himself. He typically changed into animal forms during battle, such as a scorpion or an octopus, adapting to the situation. On one occasion, he also transformed into a huge, amorphous mass of darkness that greatly resembled the evil entity he had previously once been/was spawned from and could alter parts of himself at will.
  • Supernatural Physical Abilities: Aku could alter his physical capabilities to virtually any level he needed or wanted due to his magical shape-shifting abilities. He has manifested superhuman strength, speed, endurance and senses. No parameters or upper limits were established regarding these capabilities.
  • Regeneration: While Aku is completely resistant to most forms of attack, he is not invulnerable; items such as Jack's sword or magic such as divine energy can damage the substance from which he is made of. However, Aku was able to regenerate to a large degree, even against attacks such as these. These sort of assaults tend to create large, burning holes or gashes in him wherever he is struck, which Aku can close back up with effort. However, his ability to regenerate in these situations was limited. In many of his confrontations with Jack, the damage caused by the sword whittled away at his overall mass and ability to regenerate in the short term, until it tends to leave him as a very small animal of some sort, such as a frog or mouse, at which point further attacks would presumably either seal him away as Jack's father did, or kill him as Jack intended to do. Given time however, he always restored himself without being any worse for wear. Aku has also been observed to succumb to physical pain involving blunt trauma of equal mass in relevance to the size of his form at any given time, although he is shown to quickly recover from such injuries.
  • Dark Magic: Aku is an all-powerful wizard with vast supernatural powers at his command.
    • Happy Aku laser

      Aku's eye lasers.

      Eye Beams: One of Aku's most commonly utilized attacks, this ability tends to manifest as beams of white or red light that typically incinerates the objects it makes contact with. It can be used either as continuous beams of light, or as staccato bolts of energy. He has used this ability in numerous battles with Jack, and he also used it to destroy the majority of his past kingdom. Aku can also harmlessly teleport beings to places of his choosing through this power. The beams can also slice through objects like a plasma torch, or cause them to explode.
      • Aku also uses a variation of this ability to restore or recreate whatever he chooses, as he restored Scaramouche's body with the ability.
    • Remote Viewing: Using mystical forces in his lair, Aku can create images on the walls to view whatever he wishes. He tends to use this ability most often to simply watch Jack travel while stewing in his unhappiness at being unable to kill the samurai.
    • Teleportation: Aku uses this often for quick appearances or escapes, and to appear before those he has business with, such as the Imakandi.
    • Elemental Control: He could magically project and control the elements of the physical world. These abilities included​ breathing and projecting streams of fire from his body, manipulating the earth itself, conjuring thunderstorms at will, or emitting waves of sonic force. By combining fire breath with his eye lasers, Aku can also project beams of electricity.
    • Telekinesis: He has shown the ability to move, control and manipulate objects through his will alone, even from huge distances. while using this ability, his eyes tend to flash white.
    • Necromancy: Aku has been shown to be capable of animating countless dead bodies and bending them to his will.
    • Precognitive Dreams: On one occasion, Aku was shown to be capable of receiving premonitions of his own future through his dreams, which he can then act upon to try and prevent or change.
    • Possession & Infection: Aku can use small portions of himself to infect others with his evil. The only time this has been seen was when he incidentally spat up a tiny portion of himself at Jack, which, over the course of a day or so, proceeded to possess Jack, giving him the appearance and personality of Aku. On a related note, he can also use portions of himself to power machinery, as he demonstrated by doing so with the Ultra-Robots. This ability can also work on his biological offspring, since they already have his essence and are part Aku.
    • Interstellar Travel: Aku is capable of interstellar travel, well beyond the speed of light.
    • Time Travel: This was the very ability that Aku had used to send Jack into the future at the beginning of the series, though so far he only used once and was a one way portal forward in time. However due to its side-effect, Samurai Jack cannot be aged even after 50 years.
    • Object Materialization: The ability to create objects and materials out of nothing. He once used this ability to conjure treasures in the presence of the Imakandi. He also used his eye-beams to create a new body for Scaramouche.
    • Corruption: One of Aku's most powerful abilities. Using dark magic, Aku can mutate normally harmless beings into monstrous versions of themselves. During his last known encounter with Jack, he used this ability to transform three small rams into monsters to fight Jack. It is also shown that if the corrupted creature dies, the spell will be broken and the creature will transform back to its original form. Aku also used this power to curse the Well of King Ozric, then later corrupt Jack through his supposed illness. He was also able to infuse this power into techno music to corrupt teenagers in Jack and the Rave. This power extends to the fact he can create life, shown when he gave the High Priestess a sample of his essence originally intended in the use of worship to conceive the Daughters of Aku, as well as enable him to control and corrupt any and all of his offspring into his likeness, complete with supernatural powers.
  • Combat Skills: Despite never having been shown to have trained at all in any form of martial art, Aku was a very skilled practitioner of hand-to-hand combat. Though not any sort of match for Jack, he was at least capable of defending himself reasonably well against Jack during their duel, while limiting himself to human physicality. He is also shown to be a fairly skilled swordsman, as on one occasion where he stole Jack's sword, he was able to force Jack (who was armed with a sword and shield) into a defensive posture during a bout of swordplay. However, it should be noted that on that occasion that Aku was not limited in the scope of the powers he could employ.


Despite his powerful abilities, Aku has a few weaknesses. These include:

  • Color Scheme: Aku's shape-shifting was limited to his color scheme and would remain red, black, and usually green (though not always) no matter what form he took. While not particularly problematic with regard to combat, this can make disguising himself somewhat difficult (though he has still fooled Jack numerous times with his disguises, as Jack tends not to notice Aku's color scheme issues and, when he does see through Aku's disguises, it is because of Aku's personality rather than his colors).
  • Reflection: Aku's own reflection would reveal his normal form no matter what he has shifted to look like.
  • Divine Power: Though Aku could not be harmed and killed by normal weapons and attacks, even the high-tech ones, those with divine power such as Jack's katana, Odin's Gungnir, Rama's Sharanga and Ra's crook are able to do so. The Goddess of Water and her 3 elemental servants were able to harm and defeat Aku. According to Rama, Aku can also be vanquished by "the strength of the human spirit and the virtue of human righteousness" since he is the incarnation of evil. Because Jack's katana is the only physical weapon on Earth that is able to destroy him, he is reluctant to confront Jack head-on.
  • Righteousness: The power of righteousness of any living creatures are able to vanquish him. The Scotsman's music imbued with the power of his spirit was able to affect Aku at some degree and even nullify his attack. Ashi's own purity and strength of spirit were able to release her from Aku's grasp and gain control of his powers as a hybrid. In the case of anyone else he corrupted and infected, his essence would be purged from the body. The gods Odin, Ra and Rama forged Jack's katana from the very same power.
  • Time Travel: Despite capable of opening a time portal to the future once, for some reasons he is unable to travel through time. This can be seen when Ashi open a time portal to transport herself and Jack to the past, but he didn't open his own time portal to give chase and prevent them from reaching the past and save himself, instead becoming fearful as he was aware that his death was certain.
  • His own corruptive power: His corrupted power can be used against him by any of his hybrid offspring with a strong and righteous spirit. When he corrupted Ashi and turned her into his unwilling minion, she has inherited some of Aku's powers after she broke free. She aided Jack by transporting both of them into the past by producing a time portal. This allowed Jack to vanquish Aku for good and led to his downfall.

Every confrontation between Aku and Jack has resulted in the former's defeat. As the series progresses, Aku seems to grow aware of this and avoids confronting Jack head-on.

Known Forms

  • Bird: (he used this form mostly to escape) used in I, XIV and other episodes
  • Different weapons (just hands/other parts of his body): used in XXX, CI and other episodes
  • Scorpion: used in I and XXX also shown in opening titles
  • Gorilla: used in I
  • Billy Goat: used in I
  • Kraken: used in I but also shown in beginning opening titles
  • Squid: used in VIII and briefly seen in XXXVIII
  • Manta Ray: used in IX
  • Spiked Tubeworm : used in IX
  • Cobra: used in XII
  • Dragon: used in XIII
  • Chinese Dragon: used in XXX
  • Praying Mantis: used in XXX
  • Amorphous Mass of Darkness: used in XXX
  • Mouse: used in XXX
  • Frog: used in XXXIV
  • Fish: used in XXXIV
  • Giant Spider: used in XXXVIII
  • Winged Dragon: used in XXXVIII
  • Army: used in XXXVIII and CI
  • Human: used in XLVIII
  • Therapist doppelganger: used in XCIII
  • Giant Cannonball: used in XCVI
  • Spiky rain cloud: used in CI (future)
  • Giant rhinoceros beetle-like form (possibly the limits of how much he has of himself left): used in CI (past)
  • Pacman ghost-like form (possibly the limits of how much he power has remaining): used in CI (past)



Aku reveals himself.

Ikra was one of Aku's aliases, just one of several forms which Aku assumed in order to travel closely with Jack. Using his shapeshifting abilities, Aku changed himself to the appearance of a young woman with green skin, black hair and a black dress. She/He traveled with Jack across the desert, battling many dangers together.

Under the guise of Ikra, Aku and Jack had formed a close bond (at one point Ikra even saves him from drowning in quicksand). Ikra told Jack that her father, like Jack's, had fought with Aku and having lost been forced to spend eternity trapped in a ring of fire and that she was on a quest to find a magical jewel in the desert which was powerful enough to free her father. When Aku reveals himself as having been Ikra the whole time, he mocks Jack for having believed the story about her father.

The Hermit


The Hermit was another one of Aku's aliases, just one of several forms Aku assumed in order to travel closely with Jack. Using his shapeshifting abilities Aku changed himself to the appearance of an old cranky hermit with green skin, white hair and a black robe. He traveled with Jack to find the Gems of Cronus, looking for one gem to the other, in order to resurrect Cronus.

Unlike with Ikra, Jack saw through the deception and was ultimately able to turn the tables on Aku. In the ensuing battle Jack defeated and heavily injured Aku, forcing him to retreat.

Appearances in Other Media

  • Aku was featured frequently in Cartoon Network commercial bumpers from 2001 to 2007.
  • Aku makes a brief appearance in the intro to the short-lived programming block, Friday Nights. He can be seen early on standing in the city, rivaling a few skyscrapers in height.
  • Aku appears as an unlockable Nano character in the Cartoon Network MMO, FusionFall. This is his first speaking role since the passing of his previous voice actor, Mako Iwamatsu. He was voiced by Greg Baldwin.
  • He appears in both the handheld and console versions of Cartoon Network Punchtime Explosion as a boss character. He is a playable fighter in the console version as well. He was voiced by Fred Tatasciore.
  • Aku made multiple background appearances during Cartoon Network's 20th Anniversary celebration.
  • Aku was a major villain in the IDW comic series Super Secret Crisis War! in which he, Vilgax, Mojo Jojo and Mandark teamed up.



Season 1-4

  • "You! Thank you!"
  • "But it was your poison arrow and your hocus pocus that set me free!"
  • "Fool! Nothing of this world can harm me. For I am Aku, the Shogun of Sorrow, the Deliverer of Darkness, your new master. And you will bow to me."
  • "What is this? What form of insect is this? BWAHA! It is you."
  • "Have you learned nothing? Your mortal blade cannot harm me. AAAAAAAAH!!"
  • "How could this be?!"
  • "BAH!"
  • "Once again, I am free to smite the world as I did in days long past."
  • "Who dares to summon the Master of Masters, the Deliverer of Darkness, the Shogun of Sorrow, Aku!?"
  • "Fool, no mortal can hurt the great Aku."
  • "That sword. I remember that blade. I recognize your blood. You are the son of the fool who imprisoned me those many years ago. No matter, neither he nor the sword had the power to slay me forever, and neither do you!"
  • "You might have beaten me now, but I will destroy you in the future."
  • "I disagree."
  • "Do not worry, samurai, you will see me again. But next time, you will not be so fortunate."
  • "I know of your plight, Vadaquian, for you see, I am he who has taken your water and the riches within them."
  • "The boy will return. He will learn proper respect for Aku in The Pit of Hate."
  • "You will be allowed. The oceans of Aku will be your new home. But you will pay homage to me by constructing statues in my likeness. Once a month, a monolithic tribute will rise from the depths of the ocean to remind all who is the master of this world. Now begone!"
  • "What information can be considered great for the immortal Aku?"
  • "What impertinence is this? Show me the fool!"
  • "HA! HA! HA! HA! So fate has arrived. Many years have gone since that day. And now my formidable foe, you will pay for my pain in the past with your pain in the future. HA! HA! HA! HA!"
  • "He is stronger than I remember. But no matter. For you see, little Samurai, the world is mine! My eyes and ears are everywhere, nothing you do will go unseen! Quest as you may, but we will meet again when I see fit, in a time and place of my choosing! And it is I who shall put an end to the war started in that age long past, Samurai Jack! Bwa-ha-ha-ha!"
  • "Fool!"
  • "Useless bounty hunters! Is there no fighting style that can defeat his?... Yeeeeees. No fighting style can defeat his."
  • "MAAAH! The sword!"
  • "This is not over, Samurai! We shall meet again!"
  • "Who dares to summon.. Oh, it is you."
  • "For eons I have terrorized this land. Every miserable creature trembled at the mere mention of my name. The pitiful people fright before my awesome power. But now, I am openly mocked by these measly urchins. Tales of the Samurai's heroics have spread through the world like a virus, but I will cure the world of this plague of hope. I will unleash such evil that even the most innocent soul will be consumed by terror!"
  • "The spear struck the beast, transforming him into... beef jerky!"
  • "Once upon a time, there was a little girl with an adorable red cape and GREAT FLAMING EYEBROWS, who was beloved by all."
  • "The wolf attacked Lil Red Hood, not knowing that Lil Red Hood had laser eye beams, great combat skills, and a powerful uppercut that freed Lil Red's grandmother from the evil bowels of the wolf."
  • "Not so fast, Samurai!"
  • "Your efforts are in vain, Samurai! This gateway into the past is forever... huh? Beyond your reach!"
  • "Poor Samurai. Once more you failed! As you lie smashed and defeated, so lie your hopes of going home. A-ha ha ha ha ha! Till we meet again."
  • "Samurai fool! Your efforts are in vain again. This gateway to the past is once more beyond your.. reach? You can fly?"
  • "YE-YEOW!! The sword!... The Samurai!"
  • "As far as the eye can see, the land is deoslute and full of despair. Shadows crawl across the Earth and block out the light. Darkness oozes from every crevice. Hope has been eradicated. Only terror reigns. Yet, there is one that mocks my omnipresent evil with his existence. He possesses a sword which could destroy me. They call him... Samurai Jack!"
  • "Despite my efforts, he has not yet been destroyed. But now I, Aku, dark lord of all darkness will make the final move and annihilate Samurai Jack forever."
  • "From deep within The Pit of Hate, I summoned: Demongo!"
  • "You are one of my most powerful Minions. You possess the ability to steal the essence of the mightiest of warriors or the deadliest of beasts.You have never failed me."
  • "Find Samurai Jack! Destroy him! And enslave his essence!"
  • "You have failed me, Demongo."
  • (on forgiving Demongo) "Hmm..... No!"
  • "Once again, the saga continues."
  • "Samurai, samurai. Why won't you DIE!?"
  • "Foolish, unknowing, innocent samurai. Little do you know that the path l have chosen for you will lead you to your doom!"
  • "You can run but you cannot hide 'cuz I can smell your blood!"
  • "I will get you yet, Samurai!"
  • "Vamenos, muchacho!"
  • "Even without deception, without mystic weapons, you will fall against the powers of Aku!"
  • "Bah, I say. BAHH!"
  • "Now let us test your enchanted steel against the power of the Titans!"
  • "Bye bye, samurai."
  • "No, I will not fight you today. Oh, I don't feel good."
  • "I seek to foil the samurai! To destroy his dream of returning home and to destroy all who stand in my way!"
  • "You worthless, wrinkled grub! I'll have you for dinner, you worm! I'll eat every last monk in this fold, I'll devour you all just as I had consumed the samurai! HA!! HA!! HA!! HA!! HA!! HA!!"
  • "I am Aku, this world is Aku, and everything in it is Aku!"
  • "Extra thick!"
  • "Do it yourself!? Yesssss."
  • "Yes. It is I, Samurai Jack. How incredibly observant you are."
  • "Aw, put that thing away, samurai. We all know what's going to happen. You'll swing your sword, I'll fly away, and probably say something like "I'll be back, samurai!", and then I'll flutter off over the horizon and we won't see each other for about a week, and then we'll start the whole thing all over again."
  • "I'll be back again, Samurai, you'll see! HAHAHAHAHA!!! See what I mean?"
  • "Tsk, tsk, tsk, tsk. Coulda, shoulda, woulda. It's all part of life's sweet sorrow. You're so lucky, samurai. Most of us have to live with our mistakes, but you get to DIE by yours!"

The Shadow of Aku

  • "Ha! Ha! Ha! I told you to wait! Now I will return to perpetuate my evil on the face of the earth! But you, Samurai... you will be defeated!"
  • "What? Who is that?"

Season 5

  • "WA! HA! HA! HA! HA! Whew! That was close! I didn't think you'd get here so fast."
  • "Fool!"
  • "Oh, fun fact: That was the last remaining time portal in existence."
  • "Woo, so angry. Be careful, Samurai, so much stress will give you a heart attack. Oh, what am I saying? Please continue, never mind what I say."
  • "Oh-ho! Not so fast, samurai! I know better than to mess with that sword! But before I go, I leave you someone to play with."
  • "Stop! Look at what you are doing. You're getting yourselves all over the floor. I just had it vacuumed. Out! Out! Get Out!"
  • "And I care because?"
  • "Oh! That was the old Aku. This is a new Aku. And he really doesn't care about that pathetic Samurai who wonder around like a mad fool. Haha! It's hilarious. Really. Look, I'll tell you what? you want to destroy him? Go ahead! Who cares? I certainly don't. Not one bit at all."
  • "So, tell me what's been bothering you."
  • "Well, you see, doc, it's been over fifty years already."
  • "It's been that long?"
  • "Yes, you see, that's the actual problem. Once I eradicated all the Time Portals, I thought I would just wait it out and then, the Samurai..."
  • "We don't say his name here, it is a safe place."
  • "Yes, sorry, doctor. Well, I just assumed that eventually over time, he will just... (both): DIE!"
  • "But he hasn't even aged. I mean like at all! He just grew that stupid beard, and looks like he'll be here forever! I...I just don't know if I can handle that."
  • "Yes, it seems that the initial time travel has affected the aging process. It's quite the conundrum."
  • "Yes, what is that again?"
  • "Just a confusing or difficult problem."
  • "Yes, problem. I wished there is someone who can dispose of my problem."
  • "(both): Yes, one can hope."
  • "Would somebody please... STOP ALL THAT NOISE?!"
  • "Perhaps annihilating this scum will break me out of my... malaise."
  • "Better to make it a COMPLETE annihilation."
  • "I'm sorry old man. I think you are lost."
  • "Ah, why did he bring up the Samurai? Ughhh!"
  • "You are now hearing the voice of Aku! Unfortunately, I will no longer be available for any more appointments. I'm sorry for any inconvenience this may have caused you. NOW GOOOOOOOO!!!!!"
  • "What joy!"
  • "Oh, yeah! Doo-doo-doo-doo-doo-doo-doo"
  • "But you're probably saying to yourself: (Imitating Jack's voice) Why? Why now for a sudden reunion?"
  • "Well, a little birdie told me... "
  • "I smell ME!"
  • "Yes, I smell me inside of her."
  • "But how could that be? I never... oh wait, there was that one time."
  • "Not bad. Yes, an attractive replica, but it pales to the original. Here!"
  • "Worship me, Daughters of Aku!"
  • "So she must have... Drank it? And then..."
  • "Here you are, a TRUE Daughter of Aku!"
  • "Of course it is, sweetheart. You wouldn't let your daddy get hurt by that bad old samurai?"
  • "I mean, you try and raise them right, then they run off with your mortal enemy! What's a dad to do?"
  • "Sweetheart, you have to bring out your best to defeat him, and your best is ME!"
  • "Long ago in a distant land, I, Aku, the shape-shifting master of darkness, unleashed an unspeakable evil! But a foolish samurai warrior wielding a magic sword stepped forth to oppose me. Before the final blow was struck I tore open a portal in time and flung him into the future, where my evil is law! Now, the fool seeks to return to the past and undo the future that is Aku! Not!!! Because after all these years, I have captured Samurai Jack and the sword!!"
  • "To all those fools who dare oppose me, your hero is dead! YOUR HOPE IS DEAD! I am the one true master! Let this be a lesson to all! Time to die, Samurai Jack!"
  • "Ha, ha, ha, ha! You're nothing but insignificant insects to Aku! And insects get SQUASHED and exterminated!"
  • "Flying monkeys!?"
  • "A Giant Stone Samurai? Really?"
  • "Is he dead?"
  • "How dare you talk back to your father!"
  • "Yes, I am!"
  • "...Oh no."
  • "NO, WAIT!"


Main article: Aku/Gallery


  • In the first episode The Beginning Aku's voice was low pitched making him seem more sinister however, in the later episodes his pitch got higher.
  • In the early episodes of the show, the red color of Aku's flame extended to a red outline around his eyes.
    • Aku's design experienced a number of inconsistancies across all of Season 5's episodes. Such inconsistancies include:
      • His hands having 5 fingers instead of 4 (although the 4 fingers are still shown at times)
      • The top green line between his eyes missing.
      • Expanded red lining inside his mouth.
  • Aku was parodied several times in Duck Dodgers, a Warner Brothers-produced cartoon starring Daffy Duck that ran alongside Samurai Jack's original run. In the show, Mako Iwamatsu voiced "Happy Cat", a loud and obnoxious cartoon cat with a large amount of merchandise showcased throughout the show. The Happy Cat alarm clock used by Dodgers featured Mako's voice, using Aku's distinct laugh and voice. In the episode "Samurai Quack", a parody of Samurai Jack, Aku was recreated as "Achoo", a combination of him and the Happy Cat character.
  • Many of Aku's sudden movements are accompanied by the sounds of creaking wood. This is presumably because of his body having been created from the black trees he originally took the form of.
  • Although immortal, Aku still requires sleep, shown waking from a bed in Episode XCIII.
  • After the announcement of Season 5, Aku's line of "Extra thick!" from Episode XLVII became a popular internet meme.
  • Aku was voiced by the late Mako Iwamatsu for the show's original run. He was known for portraying such characters as Splinter from the 2007 Teenage Mutant Ninja Turtles film, and Iroh from Avatar: The Last Airbender.
    • As Mako passed away in 2006, any speaking roles by Aku following would have been taken up by other actors. In FusionFall, he was voiced by Greg Baldwin (who, incidentally was also the one to replace Mako as the voice of Iroh in both Avatar and its spinoff series, The Legend of Korra), and he was voiced by Fred Tatasciore in Punchtime Explosion and Punchtime Explosion XL.
    • Interestingly, a storyboard sneak peek of Season 5 had Genndy himself attempting to imitate Aku's iconic voice. However, as it was an animatic, it's not uncommon for the person pitching the scene to do all the voices themselves as placeholders.
      • Later on, it was confirmed that Greg Baldwin would voice Aku in Season 5. Baldwin's interpretation of Aku is a mimic of Mako's original version, while incorporating the pausing mannerisms of German actor Peter Lorre.
    • Aku, throughout the series, has balanced between being a truly threatening villain and a villain designed to make the audience laugh. In the more earlier episodes, he's a fairly serious and ominous antagonist, lacking a lot of the dark sense of humor that would characterize him later on.
  • Aku shares some similarities with Hexxus, the main antagonist of the film FernGully: The Last Rainforest.
    • Both are evil, charismatic beings made from an amorphous dark substance.
    • Both are initially trapped inside a tree, but set free by different means (Aku with a solar eclipse, Hexxus via deforestation).
    • Both represent destruction of the environment to a dangerous degree
  • Despite his comedic tendencies, Aku is easily one the most cruel and immoral Samurai Jack villains, as he has destroyed and enslaved entire nations, tortures innocents for fun, starved Jack's father (and possibly many other slaves of his empire) to death, commits genocide on a daily basis, sends millions to work in labor camps presumably until death, and has taken away the free will of everyone across the universe, merely because the suffering of others amuses him. Of course, this is actually very fitting, as Aku is the embodiment of all that is evil and thus is incapable of having any redeeming qualities.
  • Ironically, it was Aku himself who provided Jack with the means to return to the past when he took control of Ashi and granted her with his powers.
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