Adventure Time Season 6 Episode 1-2 Wake Up / Escape From the Citadel >Hitching a ride on the Lich's crystalized prison, Jake and Finn find the latter's father Martin (voiced by Stephen Root), who is not what Finn expected, as they are forced to flee when the Lich destroys the Citadel while putting the prisoners under his control to begin his plan of destruction. While Finn and Jake are distracted with the Lich, Martin flees with Finn giving chase. In the ensuing chase, Finn's grass sword takes over his entire arm, causing Finn to lose it as Martin escapes. Despite this setback, the Lich is turned into a giant baby, who they leave with Tree Trunks and Mr. Pig.