Barry is one of the main identities we meet in Split, since he's the one who regularly checks in with Kevin's therapist, Dr. Fletcher. He was also the identity that got to be in charge of who could come out and take over Kevin's body, at least for a time, until Patricia, Dennis, and a few others overthrew his power. (If you'll recall, he tries to send Dr. Fletcher SOS emails throughout Split.) We don't know much else about Barry, other than that he has a great eye for fashion and hopes to be a designer.