Warhammer 40k is a bombastic tabletop strategy game with decades of intricate and often wild lore. It's also a fun dive for fans who love world-building, with plenty of books and other media available for those that don't want to play the original game. And with those years of lore come some great speculation. While the 1997 sci-fi horror movie Event Horizon is considered an unofficial prequel to Warhammer 40k, a Reddit fan theorist cleverly pulls in two more franchises to round out the unofficial movie universe -- 2000AD's Dredd and Vin Diesel's Riddick.
Redditor u/_LongLongMan's theory is a great read with plenty of detail, but most of it rests on the timeline around the development of faster-than-light (FTL) technology. FTL travel is a crucial part of life in Warhammer 40k, but with few exceptions, it involves the Warp, a realm of hellish chaos. While the Warp is a deep dive all its own, those who've watched Event Horizon with its experimental gravity drive have glimpsed the closest film depiction of it so far. The drive cuts through Hell itself, destroying the souls and minds of those who encounter it. And Event Horizon's screenwriter confirmed in a 2017 tweet that he was influenced by the world of Warhammer.
Dredd, whose best mainstream outing is the 2012 Karl Urban movie, is the next entry on the timeline. FTL is a lost technology in this world, according to the theory, with humanity having learned from the gravity drive mishap decades earlier. Dredd's world is strictly earthbound, but it still fits into the Warhammer timeline through three key details.
First, Dredd and its related 2000AD franchises had tabletop gamebooks published by Warhammer's own Games Workshop in the 1980s. Next, Dredd's Mega-Cities may be the precursor to Warhammer's Hive Cities, complete with its Judges becoming the visually similar Adeptus Arbites. And finally, the increasing mutations and cults that form the underground of Dredd could be attributed to the early influences of Chaos. Chaos and its Gods are the metaphysical incarnations of the Warp, and its touch is necessary to awaken psychics. The easiness with which Dredd's psychic judges could be corrupted is often similar to Warhammer's gruesome fates.
The theory admits to making some leaps to get the Riddick franchise to fit into the timeline, but there are still compelling tidbits to shore up their idea. Riddick doesn't make its setting clear, though there's a general consensus among film sites to place it in the 28th century. The bulk of humanity's galactic diaspora in the Riddick films don't have FTL at their disposal, and bits of background lore that suggest a lost Earth makes it possible to tie Riddick to two different early eras of Warhammer 40k. Archaic weaponry and subspecies of humans suggest Warhammer's Dark Age of Technology, while the purge of Riddick's Furyans and their abilities suggest the Age of Strife. In reality, both make sense, it's just up to preference.
In both scenarios, the Necromongers from Chronicles of Riddick fit into the theory as early Chaos worshippers granted access to the Warp. With their strange psychic abilities, a drive to purge and conquer the galaxy and a version of proto-FTL at their command, the similarities to Warhammer's servants of Tzeentch are difficult to ignore. With Vin Diesel's lifetime love of Dungeons and Dragons and his imagination a huge part of the Riddick universe, it's possible he's at least aware of some of Warhammer's biggest lore mysteries and adapted them, consciously or unconsciously, into Riddick's dystopian future.
There's little that can firmly prove _LongLongMan's theory one way or another, but the work this fan did to put their thoughts into a comprehensive and interesting timeline makes it compelling. Event Horizon's all-but-canon acceptance in the lore of Warhammer sets up a strong foundation to build on, and with the thoughtfulness of how FTL and the influence of Chaos could be behind some of the events of both Dredd and Riddick, the theory holds up pretty strongly.
In the end, this theory is fanlore, but it's the best kind of fanlore, opening up a ton of fun new rabbit holes for fans of all of these franchises to root through. Warhammer 40k is a bloody love letter to strategy, a grimdark future of gore and strife, but it thrives on fandom love and its moments of satire and black comedy. It's the same feeling stories in the worlds of Riddick and Dredd can offer, and that might be the most potent tie between them all.