The Testament of Sister New Devil

In a world where the line between humans and demons is constantly tested, a young man's life takes an unexpected turn when his eccentric father suddenly announces his remarriage. Not only does he gain two beautiful stepsisters, but he soon discovers they harbor a dark secret: they are, in fact, powerful demonesses. One is a succubus, the other a fledgling demon lord, both with their own intricate agendas. Now bound by a master-servant contract, he finds himself entangled in a complex web of supernatural politics, dangerous battles, and increasingly intimate situations. As he navigates this perilous new reality, he must protect his new family from rival demons and angels alike, all while grappling with the escalating intensity of his unusual domestic life.

✦ AI-drafted summary