Very nice work indeed! Your lineart and colouring are clean and confident looking and the anatomy and proportions are very good! The cape is cool, although as a suggestion, it might be neat to have that come over his shoulders a bit somehow?
He's got a neat backstory and sounds like a pretty badass character!
One thing I did notice when I was reading the description though is that you've listed his weight at 195lbs, which seemed a bit light for an 8'9", well muscled alien. According to
[link] he's about 535lbs underweight for their average of 720lbs.
Overall, kickass character and a very cool work of art.