Люция Рэргрув

As the son of King, he is the heir not only to the throne of Demon Card, but also the Raregroove Kingdom. He was an infamous legend known among the Empire as 'The Blonde Demon', a boy whose power was so great and terrifying, he was a threat to the entire world. Much like Gale Glory and King were destined to oppose each other, Lucia is every bit the antithesis to the second Rave Master, Haru Glory, as the self-proclaimed Dark Bring Master. -Wkipedia