The Fragile Threads of Power (Threads of Power, #1)

by V.E. Schwab

And Kell wanted what he always did these days. To prove that even now, without the power that had once defined his life, marked him as Antari and made him the strongest magician in the world, he was still worth something to the Grey Barron, and Lila Bard, to the palace and the empire, and himself.