Parents of 25-year-old man discovered incredible secret life he had after his death

A new Netflix documentary reveals how the grieving parents of a 25-year-old man with a degenerative muscular disease uncovered he had lived a second life via an online gaming platform.

Mats Steen, from Oslo, Norway, had been diagnosed with rare genetic disorder Duchenne muscular dystrophy, a condition which causes rapid muscle weakness to occur.

It meant that Mats' mobility became severely restricted as he got older, leading to him using a specialised wheelchair in order to accommodate his needs.

He would tragically pass away at the age of 25 in 2014, leading his family to discover that thanks to computer games, he'd been able to live a fulfilling life online.

Watch the trailer below:

Premiering on Netflix at the end of this week, The Remarkable Life of Ibelin follows how Mats' parents Robert and Trude Steen and his sister Mia discovered the 25-year-old hadn't led a lonely life as they'd feared, thanks to the online roleplaying game World of Warcraft.

The discovery was made after the Steens posted an update on Mats' personal blog announcing his passing.

In the following days, the family began to be inundated with emails from people who'd grown close to Mats online, referring to him as online alias Ibelin Redmoore.

Through the Ibelin persona, Mats lived the virtual life of a muscular nobleman and monster-slayer - with the 25-year-old enjoying multiple friendships and even virtual dates through the online gaming platform.

"You proved us wrong. You proved us so wrong," Robert Steen can be heard saying in the trailer, after learning his son had been able to live a fulfilling life despite of his disability.

Speaking about the discovery in an interview with The Independent ahead of the film's release, Robert explained how the family had tried to discourage him from spending too much time on the internet.

Thanks to World of Warcraft, Mats had lived a fulfilling life online (Netflix)

"We thought he lived, for many reasons, a wasted life," Robert revealed. "And then we get these stories sharing just the opposite.

"We strongly believed that he was lonely, that he had no meaning for other people."

He added: "We did all the right things, and we were so present in our children's lives. With one exception - and that is the digital part of their lives."

The project was masterminded by filmmaker Benjamin Ree, who reached out to the Steens after reading an article online about Mats' story and felt inspired to dive deeper into his digital life, which led him to track down and interview many of the online friends he had made.

The Remarkable Life of Ibelin premieres on Netflix on Friday (25 October).