‘Kaze no stigma’

Ayano is the heir to the house of Kannagi, a house with ties to the spirit of fire whose members are all fire users. All except for her cousin, Kazuma. After he was defeated by Ayano, his father banish him from the house in disgrace. Kazuma runs off and changes his surname to Yagami. He forms a contract with the spirit of wind and becomes a powerful wind user. 4 years later, he returns. Some killings in the Kannagi house by a powerful wind user lead Ayano and the Kannagi house into thinking Kazuma is taking revenge. Although claiming to be innocent, Kazuma is preparing for an all out war with Kannagi.

Descriptions taken from AniDB.net