‘Steve is the Jesus Christ of MCs, man. He died for all these guys.” With a chuckle, Darrell Austin is lionising his uncle Steve – who under the moniker Stevie Hyper D was the 1990s’ main man in live drum’n’bass MCing.

A swaggering, gap-toothed, stentorian town crier for the scene at key raves like One Nation and Dreamscape, he was credited with accelerating the fastchat of Caribbean soundsystem MCs into exhilarating “double-time” rapping, which defined the sound of jungle and pointed the way towards garage and grime. He also coined or popularised many of the rudeboy battle cries doing the rounds at the time: “Bad boy come again!”; “Junglists, are you ready!” Then, after dying of a heart attack in 1998 aged 31 on the eve of releasing his first album, Stevie Hyper D fell into obscurity. “When I first met Jamie, I was still very raw and bitter about how Steve’s legacy was being handled,” Austin says.

“Jamie” is Jamie Ross-Hulme, director of a new documentary, Hyper, that resurrects this little-known talent. On a video call from a Twickenham hotel a little tender the day after the film’s premiere, the 42-year-old remembers sneaking underage into a rave at Bagley’s in July 1998, unaware of Stevie’s death, and amped up at the prospect of witnessing the fast-spitting prodigy. Instead, “there was a collection box for the family. It was too weird and surreal. You could feel the void in the room.”

After Stephen Austin’s mother died in 2007, his nephew Darrell inherited much of his uncle’s memorabilia and found himself the custodian of his legacy. With only a 10-year age gap between them, the two were more like brothers; Austin’s middle name is Stephen, because his uncle had insisted he share it. As soon as he was old enough, he was accompanying Stevie Hyper D to gigs, witnessing the scene’s breakneck evolution from hardcore to jungle to drum’n’bass. “It was like a virus that took over the UK and infected everybody,” says Austin, 49, speaking from his home in Kingston, south-west London on the same call. “And everybody got a different variant.”

In the film, it’s clear how the next generation mutated the strain. Maxwell D from garage crew Pay as U Go Cartel recalls trading Jaffa Cakes in prison for the cassette tape packs that were the only way to hear live MC sets after they’d finished. So Solid Crew’s Megaman once rode round on an unlicensed moped to Stevie Hyper D’s house in Fulham to beg the jungle icon to play a community gig. “We didn’t see our stars on TV. Our stars were in the raves. Our stars were on those stages,” he says in the film.

Ironically, it was the rising waves of UK garage and grime – which both gave greater prominence to MCs than drum’n’bass – that contributed to Stevie Hyper D being so swiftly forgotten. Another factor was that, while he left many a loudly designed tape pack in his wake, very few of his performances were filmed. This was a major obstacle to making Hyper, until Ross-Hulme stumbled on a secret trove of footage courtesy of legendary star of happy hardcore DJ Dougal. The DJ had been so green during his entry on the rave scene that his father chaperoned him around – and had filmed many gigs, including early Stevie Hyper D appearances, on camcorder.

After a first screening of their film to executive producers, the consensus was that something was missing. This is when Ross-Hulme suggested pushing Austin, and his relationship with his uncle, more to the fore. “Jamie’s intuition picked up that there was maybe something I wasn’t telling him, or was holding back on,” says Austin.

This was more than grief. At the time of his uncle’s death, they had barely reconciled from a major falling-out, partly over Austin’s own ambitions to MC. Ross-Hulme encouraged him to explore their kinship on camera, carefully coaching him through this confessional work. It brings the film closer to the redemptive documentaries that were his models: 2012’s Searching for Sugar Man and 2018’s Evelyn, about the director’s brother’s suicide. “A core theme is ‘what could have been’,” says Ross-Hulme. “The nostalgia and the melancholy of what could have been with this amazing talent. But also what could have been with Darrell. This big emotion of regret.”

This kind of pastoral arm over the shoulder offered to Austin by Ross-Hulme was lacking in his uncle’s fast-living life, he believes. His young cohort were laser-focused on making a name for themselves, without much thought for anyone’s health. It was deep vein thrombosis, probably from the many low-cost flights he took, that ultimately killed Stevie Hyper D. In the footage from his final interview, he admits he’s exhausted. He had complained to his friends of chest pain. “Everybody being young, they’re like: ‘It’s a bit of heartburn, mate,’” says Austin, “‘Did you eat Chinese at 3am? Take a Rennie.’”

The therapeutic approach has benefited him, Austin says: “Ten years ago if we were having this conversation, I would just be vexed. Because we would walk away from that conversation without anything having been done.” The difference now is the film and the catharsis. Maybe the subtitle, to use another Stevie catchphrase, should have been: hear me now.

• Hyper: The Stevie Hyper D Story is screening at Odeon cinemas on 19 November