王の獣 [Ou no Kemono] Series by Rei Tōma

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?

Rangetsu knows she must keep a low profile in the palace if she’s to have any hope of tracking down her brother’s killer. But when an Ajin is wrongly accused of murder, can Rangetsu stand idly by knowing that Prince Tenyou has the power to prevent another horrible injustice?

Rangetsu hasn’t given up on vengeance, but nothing about the imperial palace is simple. Now that she knows and trusts Prince Tenyou, she has come to see that her most important duty is to keep him alive for the sake of all Ajin—even at the cost of her own life!

Someone in the imperial palace is trying to kill Prince Tenyou, and Rangetsu has reason to believe it might be the icy third prince, Kougai. When things turn violent on the jiju field, Rangetsu decides to confront Prince Kougai directly—and ends up as the prize in a wager between royal brothers!

Female Ajin are prohibited from serving in the palace, and so Rangetsu’s revenge depends on her ability to maintain her ruse. But when the attendant Taihaku discovers the truth and Third Prince Kougai’s suspicious are roused, will Rangetsu lose her place by Prince Tenyou’s side as well as her chance at vengeance?

Prince Kougai’s interest in his brother’s new beast-servant hasn’t waned, and Rangetsu is forced to forge an uneasy truce with him when his prying uncovers the dangerous truth about her identity. But her past isn’t the only thing the third prince has been investigating, and the palace holds many dangerous truths…

Rangetsu isn’t the only person in the imperial palace with dark secrets. Prince Kougai’s beast-servant Boku knows something about Sogetsu’s final hours, and his confession shatters everything Rangestu thought she knew about her brother’s death!

As Rangetsu and her unlikely allies follow whispered rumors through the palace in search of any hint of her brother, she finds it increasingly difficult to keep from spilling her own secret to Prince Tenyou. But revealing her true nature will upset the uneasy accord she has built between them. And even worse, it might interfere in her desperate hunt for Sogetsu!