Thor, the main character of Jyu-Oh-Sei, was abandoned together with his twin brother, Rai, on Chimera. He adapts quickly to Chimera’s environment and fights for his survival on the planet. After many near-death experiences, he learns more about Chimera and the myth of the Beast King (Jyu Oh).
Thor becomes the Top of Ocher Ring at the age of twelve, Tiz becomes his Second, and Third remains his third. He is known as the Silver Hawk for his silver hair but he hates the name. As a Top, he improves the lives of those living in Ocher Ring, even creating an air conditioning system.
Three years after becoming Top, he meets a woman named Karim, who he immediately falls in love with after saving her life. She is killed by a man Thor assumes to be Zagi. He attacks and defeats Zagi, but doesn't kill him. Zagi tells him that he didn't kill Karim. Before losing consciousness, he warns Thor not to trust Third. After becoming the Jyu Oh and riding the Dagger Pagoda orbital elevator he learns truth about why his parents were killed: They were killed because they were attached to Thor. Their orders had been to send him to Chimera. Having failed, Odin had them killed and sent both Thor and Rai to Chimera himself.
It is then revealed that Thor is the first child to be born naturally since leaving the Earth. He was artificially engineered from the DNA of the previous 37 Jyu Ohs in order to create a new race of humans who could thrive on Chimera. While trying to stop the accelerated transforming of Chimera (which would kill all the residents) he kills the previous Jyu Ohs before they can be revived to attack him.(source : wikipedia)