Monster Girl 1,000

In Monster Girl 1000, a young, orphaned warrior lives as the solitary male in a tribe of naked monster girls. The local divinity, the goddess of fertility, charges him to breed with 1,000 monster females to aid leverage the population. A pair of elf and demon females join him as he sets out to expand his harem in a strange new realm full of monster women. He needs to get a lot of women, but it's possible if he's willing to put in the hard work.