I'd like to reserve India, if I may. I usually try to shy away from larger powers, but I think India would be an enjoyable exception to my norm.

The near-complete lack of backstory pertaining to WWIII is throwing me off a bit though. Assuming I take up India, I would like to have been a relatively major participant in the war, but that's kind of difficult to pull off when I have no clue what the war was about. Who were the belligerents, what instigated the war, what sort of peace-treaty was signed? I can make due with some rather basic answers, I just need a rough idea of some sort.