This card will summon King Mickey, healing Riku slightly, stunning and hurting all enemies for a short time, and restocking Riku's deck. Stocking these cards will allow you to use the only sleight you can as regular Riku, MM Miracle. It increases the amount you are healed and the damage done to enemies. It is one of the few ways Riku can heal himself, the other being the Oogie Boogie enemy card.
Kingdom Hearts Re:Chain of Memories
In Kingdom Hearts Re:Chain of Memories, using The King's friend card along with two Soul Eater cards while Riku is in his normal form will trigger the Holy Burst Sleight. During Holy Burst, The King and Riku can move around the field back-to-back, shooting balls of Light from their Keyblades.
Using this card along with two Soul Eater cards while Riku is in Dark Mode will trigger Inverse Burst Sleight. Inverse Burst is relatively the same as Holy Burst, but The King will still shoot balls of Light, whereas Riku will shoot balls of Darkness.