Monster Heir in a Horror Game

Ethan Cole, a Monster Heir, accidentally gets pulled into a nightmare game representing Dragon Nation. Everyone thinks this F-rank weakling is doomed, but the dungeon boss suddenly kneels and calls him "Young Master"! Ethan Cole's entire family is top Monster Kings: his dad is the King of Hell, his mom is a Zombie Queen, and his sister is a Soul Reaper. Every boss in the Weird World is his relative!