Leon Cromwell

A new power among the Demon Lords, he holds the dual title of Platinum Saber. Originally a human who reincarnated from another world with Chloe 300 years ago, he was acquainted with Elmesia while acting as a hero, and became a Demon Lord after defeating Kazaream 200 years ago, ruling over the Golden Land, Eldorado. He has the appearance of a handsome man with long blonde hair. He possesses the angelic ultimate ability "Metatron," which specializes in large-scale annihilation by selecting and interfering with all mixed laws and sorting pure energy, and can freely control the strongest sacred magic "Spirit Particle Collapse," which can disintegrate anything it touches. Recognized as a friend by Guy, he has a poor relationship with Velzard.

To find his childhood friend Chloe, who went missing shortly after they were transported to another world, he gathers children from other worlds who appeared in this world despite understanding their misdeeds, including summoning Shizue as part of this effort. He also deals with eastern merchants and the Moderate Jesters to spread the method of summoning specific individuals to the western countries. He meets Rimuru at a banquet of Demon Lords in Volume 6 of the books, where he is told about Shizue's final wish. In Volume 11, he receives information about Chloe from Tia and visits the Kingdom of Ruberios, where he sees through Granbell's trap meant to provoke hostility with Rimuru, and understanding Rimuru's intentions, he trusts Rimuru and crosses swords with him, eventually reuniting with Chloe. He is initially stunned by her disappearance due to time travel, but cooperates with Rimuru and Luminous to reunite with Chloe. In Volume 12, he receives an explanation from Chloe about what happened.

He regards his childhood friend Chloe as the woman he loves most, but Chloe does not reciprocate his feelings at all. He is often teased by Ramiris, who knew him from their childhood before he became a hero, which he finds difficult. Elmesia criticizes him for being too reticent and inflexible, unwilling to open up to anyone and trying to shoulder everything himself, and Rimuru also notes that, unlike Masayuki, he is the type who is easily misunderstood by those around him, and he receives sympathy for the unfortunate lack of attention from Chloe.