Why is Marluxia stronger than the other Organization 13 members

Marluxia was only stronger than the rest of the Castle Oblivion residents of the organization, so Marluxia isn't stronger than all the other members. He was only stronger than a little over half of the members. He was seen as a threat by Xemnas and Saix and was sent to Castle Oblivion under the secret supervision of Axel. Little did Marluxia know that he was meant to be killed by Sora.