In Mass Effect, Captain Kirrahe looks like this:
In Mass Effect 3, if he survived, he looks like this:
Unlike Shiala in Mass Effect 2, Kirrahe does not have a "Why are you brown?" dialog option.
Why or how did he so drastically change appearance?
I'll accept either in-universe or out-of-universe answers, but for the latter, I strongly prefer well-substantiated information, rather than unsourced speculation about (say) the first Mass Effect's graphical capabilities.