The nuclear hero: Manhattan

The last man standing, Niko Fukushima. After world war three hits the tipping point, and the bombs finally fall, Niko is the only survivor. 40 years of fighting first in the war, and then to survive in the wasteland that was one planet earth took its toll, and finally having enough, he detonates the warhead that he found in Russia after deciding that if he went out, he would go out with the biggest damn bang he could. All didn't go as planned however, and he would soon realize, that killing himself with a sketchy warhead that he found 4 kilometers underground might have been the best idea he ever had.