I Got Caught Up In a Hero Summons, but the Other World was at Peace!

Miyama Kaito is no hero. He's just a normal university student who gets caught up in a hero summons with an actual Hero. But even "Hero" is just a ceremonial role these days, ever since the Demon Lord was killed centuries ago. In a world where demons are chill, nobles are no longer corrupt, wars are a distant memory and there are no more epic quests to complete, what's a regular guy to do? Why, build a harem, of course!