Manga Shijou Saikyou Orc-San No Tanoshii Tanetsuke Harem Zukuri

Our protagonist Oroku, is the son of a female knight and an orc. Due to his appearance taking more after his mother, he was harassed and bullied by the orcs of his village. After meeting a beautiful elf and other demi-human girls, and being rejected for his lineage, the strength of his blood awakens and plots a plan to become the strongest warrior in history in order to make a harem of beautiful women.