Maleficent

Maleficent [1]is a sorceress of awesome power. She leads the villains who seek to harness the power of darkness, urging them to be careful not to let it overwhelm them. However, unbeknownst to her, the Heartless she believes she controls are actually using her. Xehanort's Heartless unlocks her heart and turns her into her dragon form. Sora defeats and kills her but she is resurrected in Kingdom Hearts II, where she seeks a new base of operations so she can resume her intent to obtain Kingdom Hearts. At first she wants to get back at Sora, but she ends up helping him on two occasions.