The idea for this is that the apocalypse of Earth has already taken place, and the role-playing starts in the aftermath. Many humans were affected in strange ways by radiation during the apocalypse, and mutated into monsters of all different size, shape, and mental capacity. Some are beyond all thought and react on instinct only. Some, however, retained certain aspects of humanness, such as the ability to think rationally, the remembrance that they were once human, the ability to use human speech, and so on. There are also humans who remained unaffected by the radiation, and their only goal now is to survive. Electricity has been wiped out. Essentially, the world went back to the dark ages. Swords, shields, axes, no mercy. 

We need some people to role-play as still sort-of-Human Monsters, those who are somewhere on the border of having human thoughts and being a complete Monster. And we need people to role-play Humans unaffected by the radiation. Once some people are interested, I'll go into more detail.