Creed is (allegedly) a quality assurance officer of Dunder Mifflin Scranton, and is a hilarious, fictionalized version of the actor who plays him, Creed Bratton.
Creed is shadowy, old, bad at his job, beyond shady, and only delivers 1-2 lines per episode, but they are often some of the funniest. We love Creed.
Michael: Someone complained that the men's room is "whites only." Stanley, you know that's not true.
Stanley: I didn't say that.
Creed: Then why is there a picture of a white man on the door?
Ryan: Creed? Did you organize the menu book?
Creed: Oh, I thought that was more on a volunteer basis.
Ryan: No... it was mandatory.
Creed: Oh, I thought it was a volunteer thing.