Overlord: Prologue is a short story that takes place before Yggdrasil's final days. It tells the story about the founding of the guild "Ainz Ooal Gown," Momonga becoming a guildmaster and the conquering of the Great Tomb of Nazarick.

Overlord: Prologue was included with volumes 4 and 6 of the limited-edition Blu-Ray/DVDs of the first season of Overlord.