Damian Mackle (February 20, 1985) is an Irish Professional wrestler working by ring name Big Damo and Damian O'Connor. He is currently signed to WWE under the ring name Killian Dain. He wrestled regularly on the European wrestling circuit for promotions including Insane Championship Wrestling, Westside Xtreme Wrestling, Revolution Pro Wrestling, Scottish Wrestling Alliance, British Championship Wrestling, HXC Wrestling, Scottish Wrestling Entertainment, XWA, PWU and many more.