"The Eternal Harem of Yolkova"

Prompt: A big breast loving otaku dies on the way home from work and wakes up in a fantasy world in a throne room summoned by loli queen who’s full grown despite her appearance. He needs to defeat the demon lord who is the source of the eternal youth for centuries. He learns he’s in a world where all the women are loli’s staying eternally youthful. But the men still grow old and die. So polygamy is required having less than five wives is heavily frowned upon and may incur fines if you’re found not contributing to society.