|YOU'VE FORGOTTEN YOUR PURPOSE!
During his childhood and into adulthood, Jack studied with the greatest and most renowned warriors and scholars in order to prepare for his fateful battle against Aku. Though not all of them are shown, these are the ten that were shown.
It should be noted that in the real world, the teachers presented below all existed in different timeframes, some centuries apart.
Jack's first teacher was located somewhere in his home nation of Japan and taught him how to find stars and use them to navigate.
During Jack's and Ashi's wedding, he stood beside the Roman wrestler.
Jack's second teacher and a sheikh located somewhere in the Arabian Peninsula. He taught Jack how to ride horses. He also has four children.
During Jack's and Ashi's wedding, he stood with his best friend the African chief.
Jack's third teacher and the first to teach him the art of combat. This teacher was located presumably somewhere on the continent of Africa. He taught Jack how to fight using pole arms, such as the staff as well as presumably other similar weapons.
During Jack's and Ashi's wedding, he stood with his best friend the Arabian sheikh.
Jack's fourth teacher located in ancient Egypt. He taught Jack hieroglyphics and how to read them as well as various fields of academic.
Jack's fifth teacher was located in the Roman colosseum. He taught Jack close quarters combat, such as grappling, locks and throws.
During Jack's and Ashi's wedding, he stood beside the Japanese astronomer.
Jack's sixth teacher, better known as Robin Hood and located somewhere in England. He taught Jack the art of archery. He is also seen in a flashback in Episode XLIII: The Aku Infection.
During Jack's and Ashi's wedding, he stood beside The Emperor.
Jack's seventh teacher located somewhere in Northern Europe presumably in Norway, Sweden, Denmark or Iceland. He taught Jack how to sail a boat and navigate in all forms of weather at sea.
The Viking Chief from Jack and the Three Blind Archers greatly resembles him, so its possible he is a descendant of him.
Jack's eighth teacher was located in Russia. He taught Jack how to use projectiles, such as axes and hatchets.
Jack's ninth teacher presumably located on the Mongol plains in what would later become Mongolia. He taught Jack how to use a spear whilst also riding.
Jack's tenth teachers, were the monks of the Shaolin Temple located in China and led by Master Chu. They taught Jack several styles of Kung Fu and how to fight with all the weapons they use as well as the ability to utilize Chi, many of which are skills he still uses. They also taught him to use all of his senses, not just his sight and hearing, to extend his awareness and allow him to fight on any level.
They attended Jack's and Ashi's wedding on Master Chu's stead.
They attended Jack's and Ashi's wedding in Episode CI. Unfortunately, the wedding tragically ended when Ashi faded into non-existence since Jack has destroyed her father, Aku in the past, much to their shock.