If You Meet Your Father, Kill Your Father

Izuku is a half-demon mercenary who has survived on his own ever since he lost his mother as a young child. In the middle of a job, Demon Lord Hisashi identifies Izuku as his long-lost son. Izuku scorns this demon who wants to baby him. Hisashi has no idea how to handle a son with the cherubic face of a teenager, the foul mouth of a soldier, and a murderous vendetta against demons.