Luminous Valentine is a prominent character in the anime and light novel series 'Tensei shitara Slime Datta Ken' (That Time I Got Reincarnated as a Slime). She is one of the oldest and most powerful True Demon Lords, ruling over the Holy Empire of Lubelius. Luminous is known for her beauty, intelligence, and formidable abilities as a vampire. Despite her cold demeanor, she deeply cares for her people and plays a crucial role in the political and supernatural events of the series.