Koto is a minor antagonist in All Hail King Julien, the main antagonist of the fourth season, the series' final antagonist and the main antagonist of All Hail King Julien: Exiled. He is the secondary antagonist of King Julien's own story, the main antagonist being Uncle King Julien.
Koto was first shown in combat with a large, dangerous snake, when King Julien, inside a barrel, fell from a waterfall and onto the snake's head. Koto then befriended him and thanked him profusely for saving his life. He then claimed to be the last of his kind because of the fossa. As Koto and King Julien stay in a cave to keep safe from a lighting storm, Clover, who was on the search for King Julien, gets into a fight with Koto as she thought he was a dangerous savage. After King Julien breaks up the fight, Koto takes care of Clover's burnt foot and says she is like the warrior queens of his tribe.
Later, King Julien shows Koto around the kingdom as Koto questions the kingdom's defenselessness, and continues to do so as he is on a date with Clover, who willingly with him, rescues lemurs from the fossa as they give eachother dreamy stares. When the realization comes that the kingdom has been more vacant, Koto and Sage rescue the lemurs (including Clover) from the snake as they fight, then Clover and Koto later tie the snake in a knot.
Koto later bids farewell as Sage suspiciously looks on, then he returns to his kingdom where many lemurs of his kind reside. He reprimands a lemur named "Benson" for not watching after his pet snake, and he then reveals to everyone his plan to take over the kingdom.
On another day, Koto returns to King Julien's kingdom and brings his tough warrior subjects with him to tie up the citizens and imprison them behind a gate. As King Julien expresses his betrayed feelings, Koto sympathetically tells him not to fight back, because there's no way they could win. When Clover gets angry at him, he then reveals to her that he's going to make her his queen.
After Pancho helps King Julien and Maurice escape, Koto takes over King Julien's plane and wears his crown. Clover and Sage look at them from a tree and Clover, as she blames herself for what happened, asks Sage for his help.
He later died in The Day Before Tomorrow after King Julien accidentally pushed Koto's statue down as it fell on Koto. He was later seen as a ghost during the victory celebration, together with other people who King Julien 'killed'