"Oblivion" is the tenth and final episode of The Umbrella Academy's third season.
The siblings congregate in the lobby of the Hotel Oblivion, with Five vocally suspicious of both Reginald and Allison. Reginald tells them that the group has to find the seven sigils and defeat the guardians lurking about the hotel. The group splits up, but their task becomes more difficult as the hotel appears to change and warp as they move through it. Reginald summons the guardians himself, and the siblings are able to defeat three while working together.
In the afterlife, Luther convinces Klaus to return to Earth. The other siblings find him in the hotel lobby, where they then turn against Reginald... just as Five realizes the sigils they've been searching for are the stars in the lobby floor and as they square off against the final guardian. Sloane manages to beat it with intervention from Klaus and Luther.
Reginald orders all but Allison to step on a star. It is then revealed that the Hotel Oblivion is a facade for a machine that can reset the universe, and it is draining the seven's lives in order to power itself. Allison kills Reginald, but not before Reginald manages to set up a Reset Button. Despite the protests of the others, Allison pushes it.
The Hargreeveses find themselves in a new reality. Allison is reunited with both Claire and Ray, while Diego, Lila, Viktor, Five, Klaus, Ben, and Luther find themselves at the Obsidian Memorial Park, named for Reginald. They soon realize that Sloane is missing and none of them have their powers. The group goes their separate ways to explore this new world, as Reginald and his resurrected wife Abigail look on from a skyscraper.
Tropes:
- Ambiguous Situation: According to Reginald, Hotel Oblivion was created by the same entity who created the universe. Whether the God in the afterlife Klaus ends up in created it or not is unclear.
- Backup from Otherworld: As Sloane faces off against a samurai guardian that's about to beat her, Klaus uses his control over ghosts to briefly summon Luther to help out.
- Back from the Dead: When the universe resets, Luther is brought back to life along with Claire and Ray. Reginald, who was killed by Allison moments before, is also alive in the new universe.
- The Bad Guy Wins: For all his abuse and manipulations of his children throughout their lives in two separate timelines, including directly killing two of them in the past hour, Reginald manages to reset the universe and get his wife back.
- Blade on a Rope: The final guardian, wielding a knife on a rope, is the deadliest due to its range and cutting power. To compare, the siblings were able to dispatch the others while working in groups of two or three, but this one almost manages to take out all of them.
- Body Horror: The last Guardian at least is revealed to have a face riddled with holes that cockroaches crawl in and out of.
- Breaking the Fellowship: What's left of the Hargreeves sibling groups go their separate ways as Allison is moved by the reset to go be with Claire and Ray, Luther runs off in a moment of emotional stress to find Sloane, Klaus chases after him out of concern for Luther just being resurrected from the dead, Sparrow Ben immediately chooses to leave the Umbrella Hargreeves behind, Diego and Lila opt to go be happy together, and even Five and Viktor who are the last two remaining choose to go separate ways alone. This is emphasized by the group that ends up in the park all choosing different pathways to walk away from each other.
- Brought Down to Normal: After Allison hits the Reset Button, the Umbrellas and Sparrows are healed of their injuries but left without their powers. This has the added benefit of regenerating wounds, like Diego's missing fingers and Five's missing arm. It also restores Luther to a fully human body.
- Call-Back: Allison's final scene echoes her first scene in "The World's Biggest Ball Of Twine" where she again leaves a taxi to enter her Los Angeles home to see her daughter during a stormy night with a shot-for-shot recreation of her ascent through the house. Only this time, her daughter Claire is real once more, and instead of Patrick in the house, it's Ray.
- Heel Realization: As Allison watches the machine drain the lives of her family, she decides that she's had enough of allying herself with her abusive father and slices off half his head. But by pressing the button he had 'programmed', she still achieves his goal (that she stood to benefit from).
- Internal Reveal: Luther informs Klaus of Reginald's non-human nature, which is later revealed to everyone else when Allison kills him via axe to the head that chops off part of his human disguise and uncovers the alien parts underneath.
- Mistaken for Racist: "Mistaken for Xenophobic" variant. Luther tells Klaus that their father is an alien. Klaus rebukes him for his wording, saying he can just say Reginald is British. Luther clarifies that he genuinely means Reginald is a bug-like alien from another world.
- Pineapple Ruins Pizza: In the afterlife Klaus complains to Luther about pineapple being on his pizza.
- Powered by a Forsaken Child: The machine that can Restart the World is fueled by particles that exist in the bodies of the 43 superpowered children. Reginald fuels it using Diego, Klaus, Five, Viktor, Lila, Ben, and Sloane, who are almost killed in the process until Allison interrupts it by killing Reginald, though the machine had already been powered enough to create the reset button.
- Restart the World: Tucked away in a pocket dimension from the apocalypse that's decimating the universe, Reginald programs a button in the machine that he was about to press before Allison killed him. She still presses the button, though, and everyone winds up in a new universe where she gets her family back, Reginald gets his wife and status back, and everyone else is both healed from any significant injuries like chopped off body parts and left without their powers.
- Reveling in the New Form: In the finale, Luther unexpectedly reappears alongside the rest of the Academy — and finds that his clumsy gorilla-like build has been replaced with the much more normal physique he had before he was dosed with Sir Reginald's formula. Luther is immediately overjoyed and eager to show his body off to Sloane... but unfortunately, Sloane is nowhere to be found, Luther and the rest of the Academy have been stripped of their powers, and the city is now dominated by Sir Reginald Hargreeves.
- Sigil Spam: An indication of what Reginald used the machine to rewrite besides his wife's resurrection and Allison's new family is the sheer abundance of skyscrapers with Hargreeves logos in the city, implying his influence has massively increased.
- The Stinger: In a post-credits scene, Ben is seen on a train in Seoul.
- Throw the Dog a Bone: After several years of low self-esteem, social awkwardness, and being the butt of the joke that came from his modified gorilla body, Luther gets a normal body in the reset universe and is very happy about it. For added benefit, he's still shredded, just with human proportions.
