Ice King

Ice King is the tyrannical ruler of, uh, the ice. His typical diabolical plot is to kidnap a princess and force her to marry him, a plot which Finn and Jake put a stop to every time. In the game, Ice King steals Finn and Jake's garbage and plans to create and marry a princess from it. He inhabits Ice King's Castle.

Ice King was originally a human named Simon Petrikov, but the powers of his crown twisted and corrupted him, changing him into the Ice King. His fiancee Betty was his "princess", but left him when he began acting strange, explaining Ice King's incessant desire to kidnap Princesses.