Malladus

Malladus, also known as the Demon King, is the name of the primary antagonist of Spirit Tracks. He is a powerful demon that once terrorized the land that would eventually be home to the new kingdom of Hyrule, but was locked away beneath the altar of the Tower of Spirits by the Spirits of Good of the land after a prolonged war between them. The Spirit Tracks and the Tower of Spirits act as the lock to Malladus's undeground prison, and as long as they remained intact, Malladus would be safely bound within.

In Spirit Tracks, the kingdom's chancellor, Chancellor Cole, seeks to release Malladus from his prison and help him return to his former strength.

Biography

 * See also: Spirit War

Malladus makes his debut in Spirit Tracks as an extremely powerful demon that once terrorized the land and its first settlers. Over a century later, Hyrule's Chancellor Cole develops a scheme to free Malladus from his prison and unleash him upon the land once again. To do this, he causes large sections of the Spirit Tracks, which serve as the locks to his prison, to begin to vanish. This event causes alarm and suspicion with the land's monarch, Princess Zelda. Although she goes to investigate the reasoning behind the disappearance of the tracks with the help of Link and Alfonzo, Chancellor Cole drops his guise and reveals himself to be a follower of Malladus. He commands Byrne to incapacitate Link and Alfonzo, and stealing Zelda's body to use it as a vessel to restore Malladus to full power. This marks the beginning of a quest for Link to retrieve Zelda's body, restore the Tower of Spirits, revive Zelda completely, and ultimately stop the Malladus's return to  power.

After Link defeats Byrne on the top of the Tower of Spirits, he rushes up to the Altar of the Demon King where Malladus had just started taking control of Zelda's body atop the Tower of Spirits. Byrne then demands that Malladus give him a gift of power for his role in the recovery; however, Malladus only attacks him, knocking him out cold. As Malladus has not yet acclimated to his new body, though, this exertion is all that he can handle at the moment; he escapes with Cole on the Demon Train, retreating to the Dark Realm.

Anjean tells Link and Zelda to travel to the fifth temple, the Sand Temple in the Sand Realm, and retrieve the Bow of Light, an ancient relic wielded by the Spirits of Good during their war against Malladus. According to the Lokomo, the ancient relic has the power to split the soul of one from their body. Upon obtaining the Bow of Light, Byrne (now working with Link) reveals that the only way to track down Cole and Malladus is to use the Compass of Light hidden beneath the Altar of the Demon King atop the Tower of Spirits. After obtaining the compass, Link, Zelda, Byrne, and Anjean travel to the Dark Realm to confront Malladus and Cole. Link manages to damage the Demon Train, allowing himself and Zelda to climb on top of it. There, Malladus completes his resurrection, taking total control of Zelda's body. Link and Zelda then fight their way through Malladus and Cole's attacks to the front of the train, where Zelda seizes Malladus; Link then uses the Bow of Light to banish Malladus from Zelda's body. In the ensuing chaos, the Demon Train is destroyed, and all of them are thrown out of the Dark Realm.

Amidst the wreckage of the destroyed Demon Train, Malladus is forced out of Zelda's body. Zelda tries to reclaim her physical form, but finds that for some reason she can't; Malladus tries to repossess her, but he is stopped by Byrne, who gives Zelda the strength to reenter her body. As revenge, Malladus kills Byrne, to Cole's applause. At this point, Malladus possesses Cole instead, transforming him into an immense beast. Malladus is unable to maintain his hold on Cole's body for long, but as he says, he has enough time to reduce the world to ruin. After a long battle, Malladus is finally defeated by Link and Zelda, and he and his vessel, Cole, are both destroyed.

Strategy
In the battle, Link defends Princess Zelda from Malladus's fireball attacks. After which, she channels her powers with the Spirit Flute's and her and Link create a duet with her voice and the flute. This reveals Malladus's true weak point which could only be harmed by the Bow of Light. Link must then distract Malladus and have Zelda aim at his back. If done correctly, Zelda will fire one arrow into his back, causing damage. After three shots, a gem forms on Malladus's fore head and Link must strike at it and Malladus's horns. After another three shots, Link must complete the same thing again, destroying the other horn. A final arrow into Malladus's back will force him down and Link must drive the sword clear through Malladus's skull. Zelda then comes to his assistance, and together the two manage to shatter the  ruby, killing both Cole and Malladus and returning peace to Hyrule.

Trivia

 * In the final battle, Malladus bears a strong resemblance to Ganon's Dark Beast form from Twilight Princess, as well the color scheme of his appearance in The Legend of Zelda.
 * The Spanish (Spain only), French and Italian versions of Spirit Tracks refers to him as "Mallard", which is the name of the fastest steam-powered train ever built, and is also the derivative name for the English one.
 * Malladus is the second villain to possess Zelda's body, the first having been Ganondorf in Twilight Princess.
 * The theme that plays when the player must defend Zelda is actually a remix of Cole's theme.
 * Furthermore, the song that plays as Malladus's Theme after Link and Zelda finish the duet is a remix of the duet and the song that plays when traveling by train.
 * Both Malladus and Demise carry the title "Demon King." It is unclear if Malladus—or any other antagonists other than Ganon—are also incarnations of Demise. However, the fact that they share the same title seems to imply that there is indeed a relation between the two antagonists.