‘Jyu Oh Sei’
Chimera, a planet of beasts, is a prison planet for brutal criminals. Thor and Rai are twins who have an executive father, and they have been brought up without wanting for anything. However, their father is murdered, and his murderers send the twins to Chimera. It is the world where you must struggle for existence, and they will have to become beasts to survive.
Descriptions taken from AniDB.net