A popular online game, 'YGGDRASIL,' suddenly ceases all services. However, it becomes a game where players remain logged in even after the end time. NPCs begin to develop their own thoughts. A regular young man who loves video games seems to have been transported to another world along with his entire guild, transforming into the strongest magician with a skull appearance, 'Momonga.' The guild 'Ainz Ooal Gown' will embark on an unprecedented fantasy legend!