She entered the palace to avenge her brother—but the closer she gets to the truth, the harder it becomes to know whom she can trust.

In the empire, Ajin with special abilities are forced into service as “beast-servants” for the royal family, treated as little more than possessions and status symbols. After her twin brother Sogetsu is taken to the palace and later dies under mysterious circumstances, Rangetsu disguises herself as a man and enters the palace as a beast-servant, determined to uncover the truth and get revenge.

But the palace is full of secrets, and Prince Tenyou is not the cold-hearted royal Rangetsu expected. As she becomes caught up in imperial politics, rivalries, and dangerous conspiracies, her search for justice becomes tangled with unexpected friendships and complicated feelings. The King's Beast combines fantasy romance, palace intrigue, revenge, and questions about discrimination and the value placed on human life.