The King of Hearts is a character from the 1936 short Thru the Mirror. He serves as the primary antagonist in the original short. When the Joker Of Hearts alerts to Mickey dancing with the Queen, he becomes jealous and has a brief sword fight with him, which ends in the King being disarmed and falling into a pad of ink. Even more enraged, he sends out his card guards after Mickey.
In Epic Mickey
The King of Hearts, alongside his Queen, lives in Wasteland appearing in the Projector Screen Level (Thru the Mirror) to OsTown. He guards his Queen with his sword and you will loose heath pips if you get hit by the sword. He may be able to hit you, but if you spin the Queen she will twirl and some E-Tickets will appear.