Deviant Dungeon

An average night playing video games except for a sudden slip, bump and... magic summoning ritual? Our "hero" finds himself in another world at the behest of a haughty Demon Queen and is appointed her new "Dungeon Master" to fortify her dungeon against all those who would dare enter.

The Demon Queen wields world-ending magical powers and obviously has made a few enemies as she whimsically torments humanity, hopefully it is clear why she would need a dungeon to ward off any would be do-gooders who would try to stop her.