The Descent

Keller is an Insub (Insubstatiary) instead of being born to two parents genetically tied together through governmental means-- he is the result of an affair. As a consequence he is viewed as an abomination, strange, weird-- a threat. He's forced to live on the streets and survive by any means he can in a cruel and unforgiving world. He is captured, taken to the Underworld full of "mistakes" like him. It's an open arena that's constantly shifting, funded by major millionaires of the age who award millions of dollars to the last contestant alive.
He's told only this:
There is only one way to survive: kill, or be killed.