Robot Thugs

The Robot Thugs (as the leader of the Gangsters refers to them) are the fictional characters frm the series.

Appearancce
The Robo-Thugs are dressed in mafia suits wielding "Tommy guns" (Thompson sub-machine guns). One model has flamethrowers on its arms instead of Tommy guns.

Biography
They are robot assassins sent to The Blue Monkey to eliminate The Gangsters in episode "Jack and the Gangsters." However, they never came to succeed in their task, as Samurai Jack was present at The Blue Monkey and ended up destroying them.

It's unknown how the destruction of the past Aku affected their existence, but in case that Aku was the one who ordered the construction of their model series, they were likely erased from existence.

Trivia

 * It is possible that the Robo-Thugs are the same model or successor to the X-Model series.