A Card Carrying Villain with a huge ego, Emperor Zurg, coming from a long dynasty of alien conquerers, has got all the features of your average villain. Your average villain having good chances to be a client of, you know, the bigger villains, so Zurg was bound to interest the Friends at some point. He seems to have a fearsome reputation, but does relatively little to back it up. The Friends give him intimidation and occasionally boost his armies, and he's fairly good at paying off his debts - except when Hand-Drawn Space Ranger Buzz Lightyear gets involved.
Though they are unable to actually bring him over to the real world of the Toy Story universe due to his Dimension Gateway technology not being capable to make that great a jump through worlds at the moment, the Friends could still use the sentient toys modeled after him as minor troublemakers to oppose the High Council's own toy heroes. His main rival the Skeleton King from the S.R.M.T.H.F.G. world a villain who IS already the member of the Inner Circle, and boy does Zurg really hates him so much he wish he was dead for real.