Jyu-Oh-Sei

Jyu-Oh-Sei (獣王星, Jū Ō Sei, lit. "Planet of the Beast King") is a Japanese manga series written and illustrated by Natsumi Itsuki. An 11-episode anime adaptation was animated by Bones and premiered April 13, 2006 in Japan as part of Fuji TV's Noitamina programming block.

On May 2, 2009, the series made its North American television debut on the FUNimation Channel.

Story
Three hundred and fifty years have passed since humans first settled the Balkan star system, located approximately 150 light years from Earth, where a number of planets have been "terraformed" to resemble Earth. Two 11-year-old twins, Thor and Rai, live on the space colony Juno until they come home to find their parents have been murdered. The unknown assassins drop Thor and Rai on Chimaera, a secret planet used as a penal colony. Thor learns about Chimaeran society's four "Rings" and how to leave Chimera by becoming the Beast King from Zagi, who rescued Thor and Rai after they immediately run into trouble on the planet. Thor proceeds to the Ochre Ring where he gets swept up into that Ring's politics and winds up defeating its Top, bringing him closer to becoming the Beast King. After several years Thor faces off with Zagi who has violently taken over the Blanc ring and is determined to rule over and change Chimaeran society. Their encounter ends with an uneasy truce and a plan to force Juno to negotiate with Thor. When Thor finally meets the President of Juno the mystery of Thor's and Chimera's secret origins are revealed. When Thor learns the planet's inhabitants are to be sacrificed for Juno's society he destroys the scientific facility attempting to terraform Chimaera.