Rex Silverthorn was just one man...
Albeit a famous human-cyborg martial artist and merc. A soldier mercenary for the biggest power, United Merchants of the West, with business comes greed and more business. When the bombs dropped entire continents were remolded and the need for soldiers rose drastically.
One of the most famous battles called "The Graveyard" in the future.. and Rex's final battle or so he thought.
"Space Fluctuation Detected"... "Time Distortion detected"... "Entity Detected"...