Margarette is a Celestial Being and a Celestial King Candidate in the tournament that determines the next ruler of the Heavenly World. He is the father of Robert Haydn and the one who grants Robert his special power. Margarette sent his own son to the human world as a young child so that he could later be chosen as his power user for the tournament, a decision driven entirely by self-interest rather than paternal care. He is not above using underhanded tactics to ensure Robert's victory. On the surface, Margarette appears calm, composed, and even demure, but his true nature is cold and cruel. His primary motivation is the destruction of the human world, and he holds a deep disdain for humanity. As the story progresses, it is revealed that Margarette's body had been taken over by a Hellion, a malevolent entity from another realm, which used his form as a vessel to further its own goal of conquering the Celestial World. At one point, when he begins to question his own objectives, he transforms into a celestial beast and absorbs Ueki into his awakening organ, an act that ultimately pushes Ueki to unlock greater levels of his Sacred Weapons. Key relationships include his son Robert Haydn, whom he treats as a tool rather than a child, and the series' protagonist Kosuke Ueki, who becomes his primary adversary. Margarette's role in the story is that of a major antagonist operating from behind the scenes, manipulating events to bring about the fall of both the human and celestial realms. His notable abilities include the power to grant abilities to his chosen power user and the capacity to assume a monstrous celestial beast form. Very little is known about Margarette's true personality before the Hellion's possession, as the real Celestial does not appear in the story in an untainted form.