Killian Dain

Killian Dain
Dain in May 2017
Birth nameDamian Mackle
Born (1985-02-20) 20 February 1985
Belfast, Northern Ireland
SpouseNikki Cross (m. 2019)
Professional wrestling career
Ring name(s)Big Damo
Damian O'Connor
Damo
Killian Dain
Billed height6 ft 4 in (1.93 m)
Billed weight322 lb (146 kg)
Billed fromBelfast, Northern Ireland
Trained byRobbie Brookside
Debut2005

Damian Mackle (born 20 February 1985) is a Northern Irish professional wrestler currently performing on the independent circuit under the ring name Big Damo (shortened from his initial ring name Damian O'Connor). He is best known for his time in WWE, where he performed under the ring name Killian Dain.

Prior to joining WWE, Mackle won the ICW World Heavyweight Championship while wrestling for Insane Championship Wrestling. He also wrestled for numerous promotions on the British independent circuit, around Europe, and in the USA including All Elite Wrestling, Progress Wrestling, Revolution Pro Wrestling, Westside Xtreme Wrestling, Absolute Intense Wrestling, Beyond Wrestling, Premier British Wrestling, Scottish Wrestling Alliance, What Culture Pro Wrestling and IPW:UK.

On 19 October 2016, WWE announced that Mackle had signed a developmental contract with the company and had arrived at the WWE Performance Center in Orlando, Florida. He began to work in the NXT brand as part of the stable Sanity, along with Nikki Cross, Eric Young and Alexander Wolfe. In 2018, Dain, Wolfe and Young were drafted to SmackDown, where they worked as a stable until the dissolution. Then, he was drafted again to NXT, where he stayed until his release, in June 2021.