Yen Sid!

"You refer to Mickey. He, too, sought guidance here. As a king, he is good and kind. But the weight of a crown has not cured him of impetuousness. He has left with an object whose power he does not understand nor know how to control. Mickey imagines my Star Shard will be of help in his current quest. And, like you, he is eager to use his Keyblade to set things right."