Yep... He was KIA during an operation. Duke, our resident lich, infused him with a rock wyvern soul.
So now the tanker has magma breath, spits up napalm phlegm, and has flatulence that is the natural equivalent of VX nerve gas.
We'll add in the fact that he developed an interest in laser weapons and pushed for the development of laser rifles, man portable laser cannons, laser tanks, and, this is the fun one, Comanche gunships with lasers.