Many of the better anime series have a darker theme to it. I think that Jyu-Oh-Sei, fits that realm well due to the fact that they’re a bunch of young boys that are sent to a penal colony planet after their parents were murdered in a conspiracy to keep things quiet.
On Chimera, only the Beast King is allowed to leave the planet via the Dagger Pagoda. To become of the Beast King, you have to defeat each of the leaders of the rings and eventually the Beast King. And thus begins the conquest of Thor, whom tries to make it all the way to the end with the help of a few friends he meets along the way.
I would say that this series really hits home on the dog-eat-dog world and how sometimes you have to make incredibly difficult decisions, especially when it comes down to if it’s a life or death situation between you and the other guy. Alliances are also frail so whom you trust could in the end become your biggest regret.
A really good series, albeit short, but one of the few darker ones that I thought was worthwhile to buy. So if you’re looking for the box set, it’s going to put you back a little over $50USD.