Barbarian's ending sees Tess return to the Airbnb to save AJ, who has just watched Frank die by suicide. Tess and AJ manage to escape the wretched house, but the Mother is far from dead, alive despite Tess crashing her car into the monstrous woman.
At the end of Barbarian, Tess realizes that she can only rely on herself when police officers don't think that she's telling the truth about the events of the last little while. Tess gets the keys to her car from the rental home and seems to kill The Mother by running her over.
However before they could do anything a large deformed woman ran through the tunnels, grabbed Keith, and smashed his head multiple times into the wall, killing him.
Although he kills himself, it's not because he feels remorse for his atrocities, but because he was a decrepit old man at the time, and he didn't want to go to jail if AJ called the police.
To this end, the surprise ending of the film where the Mother willingly sacrifices herself to save Tess and, later, allows Tess to kill her signifies her innate trust in and solidarity with other women.
Frank is the overarching antagonist of the 2022 comedy horror film Barbarian. He is a serial rapist who abducted and raped multiple women in the underground corridors beneath his house and committed subsequent acts of child molestation.
AJ loses his gun and pushes Tess off the water tower to save himself. The Mother jumps after her and shields her from the fall. AJ finds Tess is still alive, but as he tries to rationalize his actions to Tess, the Mother revives and gouges his eyes out, killing him.
They escape to the top of the nearby water tower, but The Mother follows them up there. Because he's a massive douchebag, AJ throws Tess off the roof as he rightly assumes The Mother would try to save her 'child'. The Mother catches Tess and breaks her fall, but she's not dead.
Tess grabbed Frank's gun and slowly pointed it at The Mother's face, to which the Mother did not resist, and pulled the trigger, finally ending the creature for good and avenging the deaths of Keith, Andre, and the other people the Mother had killed years ago.
However, Cregger has provided a hint by revealing that Barbarian is based on a thought he had after reading a book called The Gift of Fear, a self-help book written by a security consultant named Gavin de Becker.
Ultimately, men are the monsters in Barbarian; more specifically, the film investigates the structures that allow and encourage men like Frank and AJ to behave as they do. They are cisgender, white men in a society that is built by and for them; both weaponize their privilege to do whatever they want.
The true monster is Frank, and somehow, The Mother is the result of his crimes. We see The Mother show fear for the first time when she's chasing AJ. He finds a room that makes The Mother stop and cower in fear. Inside the room is a much older, bedridden Frank.
AJ, a man who has himself been accused of rape, watches one of the many videotapes Frank has recorded of himself raping and, presumably, murdering several women over the years. AJ is utterly horrified by the tape; however, Barbarian director Zach Cregger does not show viewers the contents of the video.
Towards the end of Barbarian, AJ found Frank who was bedridden and non-verbal. Likely Frank didn't have much time left, but AJ's discovery of his lair led him to make the decision to end his life.
Keith went down into the labyrinth, only for Tess to try to help him after he got attacked in the shadows. Mother then crept out of the dark, smashing his head into the wall. Interestingly, when she took AJ, he panicked even more, which Tess warned about as she knew Mother would also kill him.
The naked woman, referred to as The Mother, turns out to be the progeny of a man named Frank who's also still alive in the deepest recesses of the house's winding basement tunnels. Frank was a murderer and a rapist who abducted women, and one of them gave birth to The Mother.
Cregger recalled a chapter that encouraged “women to pay attention to these little minor red flags that men can give off in day-to-day situations.” This can be seen in the opening scenario between Tess and Keith in small moments like when Tess realizes he opened her bedroom door in the middle of the night.
The previous owner of the house, Frank (Richard Brake), proves to be the titular barbarian, and the most monstrous creature in the film. Frank is a serial killer and rapist, who has been kidnapping women for decades, and imprisoning them in that squalid room in the basement.
They are a symbol of evil and death. Colloquially, however, snakes are not animals, but people. They are backstabbers — the barbarians — who have a tendency to manipulate situations to craft a narrative that presents themselves as innocent.
