That Prince Is A Girl: The Vicious King's Captive Slave Mate

In a cursed world scarred by an ancient war between humans and beast-like Urekai, Emeriel dresses as a prince to protect her sister and family. Centuries ago, the savage beast king Daemonikai spread a deadly plague among humans, leaving women rare and easily endangered. When her sister is sold to the volatile king, Emeriel follows her into his dark fortress, where she becomes bound to him by an unbreakable spiritual connection. Haunted by strange physical pain, scheming lords and brutal guards, she must keep her real identity hidden while battling hatred, fear and a pull she cannot control.