Malladus is the main antagonist and final boss in The Legend of Zelda: Spirit Tracks.
Malladus, The Demon King, once ruled over a frightened Hyrule, until a rebellion broke out. As a result, Malladus could not be destroyed but was shackled by the Spirit Tracks. In the beginning of the game, though, the Spirit Tracks are disappearing and Malladus is trying to break free. On your way to the Tower of Spirits, Chancellor Cole steals Princess Zelda's body for Malladus's use, due to it having the Sacred Power of the Spirits. Malladus is successfully revived, and takes control of Zelda's body. At the end of the game when Link finds the Dark Realm, he faces Malladus and frees him from Zelda's body. He then takes Chancellor Cole's form and transforms it into a huge beast, which Link then proceeds to destroy. He sends the Lokomo Sword straight into the jewel Malladus's forehead, thus forever destroying him and Chancellor Cole.