Juuni Kokuki, Magi: The Labyrinth of Magic Recommendations
Both have main characters that try to find out who they are. Both have beings that choose kings and revolve around the same kind of era and place. Magi is more lighthearted that Juuni Kokuki (at least right now) and J.K. is rather violent.
The Twelve Kingdoms & Magi both have main characters (Aladdin & Yoko) gone to a unknown fantasy based magical world, where they are forced to participate not only in wars with other kingdoms, but also in civil ones.
Kinda had the same sort of feels, kings chosen by others etc.
Only Magi had more fighting, the rest was somewhat the same.