The Mirror Prince — Violette Malan

MAX RAVENHILL THINKS HE'S HUMAN...
but he's wrong. He's been given false memories by his Wardens, who don't want him to realize that he's been alive for over one thousand years.

Max and his Wardens are Riders--the Faerie folk--and back in their Lands Max was the Prince Guardian, Keeper of the Talismans. - As the Prince Guardian, Max lost a civil war and was banished to the Shadowlands, the human country. To prevent his escape, his memory was bound, along with his dra'aj, the magical energy of Faerie. His Wardens are with him to make sure the powerless Exile isn't accidentally killed by humans.

The Banishment is nearing its end when Warden Cassandra Kennaby gets an unexpected warning that Max is in imminent danger from his old enemy, the Rider now known as the Basilisk Prince. When the warning is confirmed by the appearance of the Hunt, the only way Cassandra can save Max is to risk returning him home before the end of the Banishment. Max finds himself in the Lands of the People, where no one and nothing--not even the Landscape itself--does what he expects. Cassandra and Max find that the dra'aj of the Lands has been waning during the Banishment, and the Basilisk Prince's power has been growing. Max's old supporters desperately need him to prevent the Basilisk from declaring himself High Prince and destroying the natural Cycles of the Lands. But it isn't really Max they need--it's his true self, the Prince Guardian. Max must decide whether to give up the only life he knows in order to become someone else. For only then can he hope to fight an ancient enemy he doesn't even remember.