Keyblade Master

When people pass the Mark of Mastery, they become Keyblade Masters. There are a lot of them, Aqua, who's trapped in the Realm of Darkness. King Mickey, who trained under Yen Sid and Eraqus, who's been slain by Master Xehanort.

Masters

Master Aqua

Master Yen Sid (retired)

Master Eraqus

Master Mickey Mouse

Master Xehanort

Master Mario (completed exam)