The King's Beast

is a fantasy shojo manga by Rei Toma. It began serialization in the manga anthology Cheese! in January 2019. Viz Media has licensed it for release in English.

Plot
Ajin are people who bear the attributes of beasts, and in this kingdom they are forced to serve men in the military and women in the brothels. The Ajin boys who show signs of special abilities are conscripted to serve in the imperial palace as beast servants—status symbols and shields for their royal masters, to be kept or discarded on a whim. When Rangetsu's twin brother Sogetsu showed signs of such abilities, he was ripped from her arms and given to Prince Tenyou as a beast servant, where he quickly fell victim to bloody royal intrigues. Now in a world that promises only bitterness, Rangetsu's one hope is to disguise herself as a man and find a way into the palace to avenge her brother!

But Prince Tenyou is not what Rangetsu expected, and the political currents in the palace run deep and strange. Does Rangetsu have any chance of finding justice for her brother, or will she become just another Ajin casualty in the game of kings?

Official

 * Official English site