AgentofSocialMediaChaos's Waifu of the Day Season 4 Episode 312 Zelaios Akaba

This isn't an isekai just an ecchi fantasy similar to Peter Grill. It's about a man who has a medical condition that causes him to fall unconscious whenever he gets aroused. Unfortunately for him one day it turns out his sperm will create either the next Chosen One or the next Demon Lord depending on who the mother is so he has multiple monster girl waifus both good and evil trying to get pregnant with his baby. As of currently in the series 9 have been successful(8 Chosen One mother candidates and 1 Demon Lord mother candidate)