Ok I got this novel idea one day and Id like to develop on it with help.
So pretty much, and the waste and radiation society had left behind had an effect on nature and now the world is festering with monsters. Everyday is a fight for survival to them. Society has been set up underground. The country is separated by levels, each level is referred to as a plate, the lower underground you go the more luxurious or important plates are and the farther up you go the get progressively worse. And the top level is a current battle field that shifts from plate 2 to the ground level.
Ill draw a picture of what I imagine later.
And for the story I was thinking that at one point before we had to start fighting that the top plates were the luxury ones and one day it was suddenly attacked by monsters, killing all of the inhabiting residents, or so everyone thought. What happened was the ones that survived ran and felt betrayed by their peoples lack of help. So they grew thirsty for revenge and trained and multiplied. Now they seek to control the monsters and kill everyone that opposes them, in their goal to control the city Gaea.
Two options we could play as those seeking revenge and live above ground in that society.
Below ground and play as citizens or soldiers on the top plates.