Jyu-Oh-Sei: Planet of the Beast King

The twin brothers Thor and Rai Klein are orphaned after their parents' murder and sent to the terraformed planet of Chimaera. Chimaera is home to carnivorous plants and divided into four Rings, where humans live in a hierarchical structure. The twins meet Zagi and learn that the Jyu Oh Sei, or the conqueror of the four Rings, is the only one who can leave the planet. Thor decides to survive and uncover the truth about his parents' death and humanity's fate.