"Chunk may be hideous radioactive mutant, but Chunk pretty on inside and not need your judgements!"
The nuclear fallout left the land barren and radioactive in the years following. The creatures that were the strongest survived, but not without suffering great changes and malformations considered terrible and ugly. You were born to this face, mutated and stretched and broken, and for you it is all that you know.
If you are to continue to survive, you will need to fight. Destroy those who are soft and take what you need. Do not rest for fear that someone stronger and more suited to this land will find you, in turn.