Tank

He's the subject of my recent colored pencil tutorial:

This guy has been in my head for a long time, as a lot of my characters had earlier versions that I kept redesigning. As of now, his name is Tank.
He was found inside an abandoned tank by some folks in a small village. He was 3 years old at the time and probably just climbed in out of curiosity. He didn't know where he came from and didn't seem to care. Tank was an odd kid, not very interested in people to the point that he rarely makes conversation or even eye contact, and terribly agoraphobic. He was only comfortable inside small spaces, especially tanks. He's come to know them inside and out, and is particularly skilled with weapons systems. This got him a job venturing through the desert with a group of bottom-of-the-barrel army recruits, killing horrific mutant creatures that for whatever reason are spawning out of control.  The crewmates have come to expect Tank's odd behavior, whether it be his refusal to leave the tank or his insistence to sleep inside a cupboard with his bear, Crusty.