Adrian McCallum has passed on at the age of 36 and the cause of his death was not made known to the public.
A few months earlier, the Scottish wrestler's attempt to save a teenage girl who was his neighbour from a fire accident failed.
The 18-year-old named Natalie Merry died at the scene while her boyfriend Alistair Innes and her mum Jennifer Merry managed to escape.
The Daily Record has reported how McCallum gave an account of the incident which happened earlier in the year.
He said: "I became aware of a boy hanging from the top window so I yelled at him to jump. I caught him as he came down and then tried to break down the front door.
"The poor girl was still inside. I could hear her screaming."
McCallum was the reigning Insane Championship Wrestling (ICW) world heavyweight champion and also competed in the WWE and TNA during his career.
The Scotland-based ICW announced his tragic death and said in a statement: "We are heartbroken to learn of the tragic death of ICW World Heavyweight Champion, Adrian 'Lionheart' McCallum.
"Adrian was a mainstay of ICW and British professional wrestling. Most importantly, he was our friend. His passing leaves a huge hole in the lives of those who knew him."
No further details about McCallum's death have been released and high-profile names in the wrestling community paid tribute to the Scot after the news was announced.
WWE wrestler Cedric Alexander said he was "crushed" to hear of McCallum's death, while fellow WWE star Paige said she would be "forever grateful" to have known him.
Pete Dunne, the longest-reigning WWE UK champion, tweeted: "I always looked up to Lionheart's professional approach to wrestling when it was far from that at the time. People like him were pivotal in the growth of a scene that has lead to so many people being able to do this for a living."