Last Round Arthurs Vol 1 Light Novel

Last Round Arthurs by Taro Hitsuji. A Fantasy light novel rated Teen, published in English by Yen Press.

A battle royale has begun among the descendants of King Arthur's knights, all fighting to claim the title of his true successor. Lazy delinquent Rintarou Magami ends up as the retainer of Luna Artur, the most hopeless candidate of all, and he has secrets of his own.