Encountering a new stepsister in the bathroom is an awkward way to create a positive first impression, a lesson Basara Toujou quickly learns. When his father abruptly brings home two stunning girls and presents them as new family members, Basara has no choice but to welcome the Naruse sisters. They are the voluptuous red‑haired Mio and the small, silver‑haired Maria. However, the girls soon reveal themselves as demons—Mio is the sole daughter of a former Demon Lord and Maria serves as his devoted succubus. Basara must admit that he once belonged to a clan of Heroes, sworn adversaries of the demonic forces. Yet, as he grows attached to his new sisters, Basara chooses to shield them with his abilities and establishes a master‑servant pact with Mio to guard her. The Heroes keep a close eye on his actions, while relentless demonic threats loom. Basara must perform the impossible to protect his newfound family. Meanwhile, the guardian hides a personal darkness that continues to haunt him. His secret shadows the path he walks beside his sisters today.
Production IMS Japan