Warning! SPOILERS for BarbarianMuch of Barbarian's storyline unfolds in a labyrinth of terrifying underground tunnels, though the movie keeps the origins of this setting shrouded in mystery. The first half of the movie presents a series of red herrings in which it is hard not to wonder whether Bill Skarsgård's Barbarian character, Keith, is a kind stranger for letting Tess stay for the night or a man with sinister, ulterior motives. However, when Tess discovers a secret room in the rental's basement and a long stretch of tunnels connected to it, it becomes evident that Keith is nowhere close to being Barbarian's antagonist, and that more chilling dangers await Tess in the rental from hell.
While Barbarian never reveals who constructed the underground tunnels, it is likely that Frank, the house's original owner, built them. A flashback hints that Frank abducts women from his neighborhood, imprisons them in his basement, and then sexually assaults them. The homeless man Andre, who later rescues Tess from the basement, also reveals that Barbarian's primary antagonist, Frank, abused the children of his victims. This suggests that, to keep anyone from learning about his crimes, Frank likely built the tunnels to hide the women he abducted, and that he kept expanding those tunnels while carrying out his misdeeds. Barbarian's writer-director, Zach Cregger, more or less confirmed this in an interview (via Hollywood Reporter) by stating, "In my mind, he [Frank] built them."
Why Frank Was Never Caught In Barbarian
Although Barbarian never confirms this, it is likely that people from Frank's neighborhood were gradually leaving because of Frank's secretive crimes. Since Frank kept his victims in the hidden tunnels of his home's basement, no one probably found enough evidence to prosecute him for the sudden disappearances of women in the neighborhood. As more and more people moved out and avoided the area because of its safety concerns, Richard Brake's Barbarian character, Frank, found more liberty to continue his evil deeds, with the likelihood of him getting caught dwindling with time.
Why Frank Lived In The Underground Lair
Frank was probably the only one left behind in his neighborhood. To make his home seem as abandoned as the rest of the houses in the neighborhood, he likely snuck inside his underground tunnels full-time. By doing so, he avoided raising any suspicion and buried his crimes with himself underneath the tunnels of his basement. The homeless man, Andre, also claims that nobody ever makes it out of the house, which suggests that the tunnel also proved to be an effective place for Frank and The Mother to hide the bodies of their victims.
Despite the confirmation from Zach Cregger, it is hard not to wonder how Frank single-handedly managed to build a seemingly endless maze of underground tunnels. Perhaps a sequel for Barbarian will dive deeper into the depths of the tunnels and unravel the darker mysteries and monsters they withhold. Conversely, maybe a Barbarian prequel could better explain the details surrounding Frank's crimes and the origins of his underground tunnels.