Damian Mackle is an Irish Professional Wrestler known by the ring name Killian Dain. He is best known for his time in WWE. He has worked in various independent promotions including the Westside Xtreme Wrestling, Revolution Pro Wrestling, Premier British Wrestling, and Scottish Wrestling Alliance. In 2016, he made his debut in NXT alongside Nikki Cross, Alexander Wolfe, and Eric Young.
Damian Mackle was born on 20 February 1985, in Belfast, United Kingdom. He was a fan of football since his childhood. Damian was a big fan of Manchester United. He also used to play Rugby during his school days. As a child, he was attracted to the sport of professional wrestling. Damian also was inspired by Sting, Ultimate Warrior. He was married to a fellow wrestler Nikki Cross in 2019.
Professional Wrestling Career
Damian Mackle began his career in NWA Scotland. He was trained by Brookside. Soon he started to work for the Scottish Wrestling Alliance at the age of 20 as Damian O'Connor. He worked as a tag team with Scott Renwick. They two won multiple tournaments together and tag team champions including in the SWA, W3L, and SSW. Later on, they went to focus on singles matches and won the Heavyweight titles SWE and XWA. In 2009, he went on to become a trainer in Source Wrestling School and trained various wrestlers including Joe Hendry, Joe Coffey, and Nikki Cross.
Insane Championship Wrestling
Damian worked in the ICW from 2009 to 2018. He made sporadic appearances in the promotion. He debuted various gimmicks during his run in the company. One particular gimmick was "Big Damo." In 2016, Damo defeated Chris Renfrew for the ICW World Heavyweight Championship. He was the first Irish Champion. Later Damo lost the Championship to Joe Coffey.
In 2014, Damo challenged Drew Galloway for the Evolve Championship but was unsuccessful. In 2014, he wrestled in Revolution Pro Wrestling Hiroshi Tanahashi, Shinsuke Nakamura, and Tommaso Ciampa. In 2016, he wrestled Roderick Strong, Matt Sydal, and Dalton Castle.
Total Nonstop Action Wrestling
In March 2016, Damo challenged Eric young for the TNA King of the Mountain Championship. But he lost the match. On March 8, Damo competed in the King of the Mountain match against Eric Young for the King of the Mountain Championship. Damo was defeated in this match.
In 2016, Damian Mackle made his debut in WWE. He performed under the ring name Damian O'Connor. He made his in-ring debut against Rich Swann at an NXT live event and was successful. In December 2016, he was aligned with a stable named "Sanity." It was a heel faction consisting of Nikki Cross, Alexander Wolfe, and Eric Young. In January 2017, he joined the faction after attacking Tye Dillinger.
Source - WWE
Killian Dain in the Sanity faction.
Killian Dain then started to make appearances with Sanity and attacked Chris Atkins on the January 25th episode of NXT. On February 8, 2017, his faction defeated the team of Tye Dillinger, Roderick Strong, and No way Jose. At Wrestlemania 33, he gained his spot among the final three in Andre the Giant Memorial Battle Royale but was eliminated by Mojo Rawley. In July 2016, Dain was defeated by Drew McIntyre in the Contender match for the NXT Championship.
In March 2018, he was named among the six participants in a ladder match that was set to take place at the NXT Takeover: New Orleans for the inaugural NXT North American Championship. Unfortunately, he lost the match. In 2018, Superstar Shake-up Sanity was drafted to SmackDown where they attacked the Usos. The following week they lost to the team of Usos and Jeff Hardy. Then the Sanity faction went on to have a feud with The New Day. They faced off the New Day in a Tables Match at Extreme Rules in which surprisingly Sanity won. On July 24, They once again faced New Day in a No.1 Contender Tournament for the SmackDown Tag Team titles and were defeated by the New Day. After a brief hiatus, Sanity returned to the April 2nd episode of SmackDown and was defeated by the Miz in a three-on-one Falls Count Anywhere match.
Source - WWE
Miz vs Sanity three-on-one Falls Count Anywhere match.
In 2019, Dain returned to NXT Live events, and the faction was disbanded. Dain played a couple of matches. Dain defeated Hailey on the May 16 episode. Dain attacked Riddle following a match against Arturo Ruas. This led to a feud between the two. In September 2019, Dain faced Riddle in a match to determine the contender for the NXT Championship in a Street fight in which Matt Riddle had the upper hand. Thus bringing an end to the feud. Shortly after, he went on to have a triple threat match against Pete Dunne and Damian Priest in the NXT Takeover: Wargames to determine the contender for the NXT Championship. In which Pete Dunne won the match. After that Dain didn't have the chance to wrestle in NXT during the pandemic. In June 2021, he was released from WWE.