Lord El-Melloi II Sei no Jikenbo, also known as The Case Files of Lord El-Melloi II, is a mystery and fantasy series set in the Fate universe. It follows Lord El-Melloi II, a former participant of the Holy Grail War, as he solves magical mysteries and navigates political intrigue in the world of mages. The series combines elements of detective fiction with the rich lore of the Fate series, offering captivating storytelling and intricate character development.