Yea, I think he could take Kirby out.
Hehe.
Edit:
You'd keep an element of surprise if you could grapple, dude. A physique like that, everyone expects ground N pound. You probably have good takedown defense as a virtue of your build, but yea, judging by the look of you, I see you excelling at overpowering and using force to gain position. You wouldn't need to excel at striking ability, because you seem like the kind of guy who's more at home up close and personal, whether on the ground or up top.
Only thing I'd worry about with you is speed and reaction. Maybe that would be something you'd focus on in training.
No matter how big you are, you can only take so many bullets if ya know what I mean.
