Upstart Demon Reincarnation Kit

A boy with high-spec status was promised a life as a winner from birth. However, he was unable to enjoy even a fragment of that life before falling into a brain-dead state. When he came to, he had become a ghost. He negotiated with a reincarnation deity to obtain special perks, and was reborn as the child of a half-demon, half-human slave with one parent being a demon. There, he made a resolve. To live as a demon would—freely and as he pleased—and rise to the top.