Thor, the protagonist of Jyu-Oh-Sei, was abandoned on the planet Chimera along with his twin brother, Rai. He quickly adapts to the harsh environment and fights for survival, facing numerous life-threatening situations. Through these experiences, he learns more about Chimera and the legend of the Beast King (Jyu Oh).
At the age of twelve, Thor becomes the Top of Ocher Ring, with Tiz as his Second and Third as his third in command. Known as the Silver Hawk due to his silver hair, he despises this nickname. As Top, Thor improves living conditions in Ocher Ring, even installing an air conditioning system.
Three years into his leadership, Thor saves a woman named Karim and falls deeply in love with her. However, she is killed by someone Thor believes to be Zagi. After defeating Zagi without killing him, Zagi reveals that he did not murder Karim and warns Thor not to trust Third before losing consciousness.
After becoming the Jyu Oh and riding the Dagger Pagoda orbital elevator, Thor discovers the truth about his parents' deaths: they were killed because they were attached to him. Their mission had been to send Thor to Chimera, but failing that, Odin had them killed and sent both Thor and Rai to Chimera himself.
It is revealed that Thor is the first naturally born child since leaving Earth. He was artificially created from the DNA of the previous 37 Jyu Ohs to establish a new human race capable of thriving on Chimera. In an attempt to stop the accelerated transformation of Chimera, which would kill all its inhabitants, Thor kills the previous Jyu Ohs before they can be revived to attack him.
