The ID Ruin can refer to one of two specialists:
Born into a military family and raised in a tough neighborhood, Donnie Walsh grew up fearless and headstrong.
Joining the army straight out of high school, Walsh is an infantry soldier through and through; the battlefield has become his second home.
He is suspicious of covert ops and anything that operates outside of the established chain of command, viewing them as dishonorable. He prefers a straight-up fair fight, and knows that there's never a substitute for good boots on the ground.
Now cybernetically augmented, he uses his unique abilities to rush headlong into the fray, meeting his enemies with sheer unadulterated and overwhelming force!
- Donnie "Ruin" Walsh - callofduty.fandom.com