Gertrude no Recipe

Sahara is a high school student whose routine life changes after encountering Gertrude, a 100-year-old demon who appears as a teenage boy. Gertrude was artificially created from parts of other demons using a formula from an ancient spellbook. He seeks to locate the original recipe to understand his origins and ensure it is destroyed to prevent future use. Sahara joins Gertrude in this search, offering her help as they are supported by a group of humorous and harmless demons.