Demon Progenitor Development Project

Thanks for the invitation. I've transmigrated, and my life here is in ancient times, where there's practically nothing. No gourmet food, but food that causes athlete's foot if you eat too much; no beautiful women, but noble ladies with white powder and black teeth who look like monsters. Fujiwara no Shugo, now with a new name: life is tough! His only luck is that he's transmigrated into the body of a powerful nobleman, the kind who wields immense power. Until later, Fujiwara no Shugo discovers a sickly baby named Ubuyashiki. Damn! This is Demon Slayer! — Fujiwara no Shugo raises a young version of Muzan in his home, showering him with affection, attracting a lot of attention. Until someone asks him if he's trying to emulate Genji. Fujiwara no Shugo...