Mangler explains his evil plan to the Forbbiden Arts
Mangler is the leader of the flying squirrels and a loyal follower of the Forbidden Arts out of fear for his life, making him an antagonist not because his life was in danger but because he later showed no remorse for the wicked deeds he carried out for the Forbidden Arts. He is the oldest member of the flying squirrels, but he is ruthless, relentless, and bitter - and he refuses to accept the Scullions' failure to kill the Swan Princess, fearing whatever punishment the Forbidden Arts has in store for him should they fail. In an attempt to kill Odette, he inadvertently shoots Jojo as a squirrel grabs the shooter making it shoot off target, but the young squirrel is quickly revived because the intended target gives him an antidote for the poisonous dart. The other Scullions show outrage towards his actions, but he makes another attempt to kill Odette using one of the many boobytraps set around the flying squirrels' campsite. However, the true prophecy is revealed (apparently as a result of Odette saving Jojo's life) and the flying squirrels turn against Mangler, realizing that he had been lying to them. They banish him from the Scullions and he is exiled from their territory - just as he had done to Scully years before.
Even after his banishment, he still shows great persistence in killing Odette, perhaps still fearing the Forbidden Arts' wrath. He even goes so far as to follow her and Scully on their way to save Alise, hoping to succeed in his final assassination attempt. He and Scully partake in combat after Scully tries to defend Odette from an ambush, during which the two fall off of a ledge. Scully is shown to have made it out of the chasm (though it is never revealed how), but Mangler is never seen again, therefore insinuating that he most likely perished from the fall.