Netflix's The Umbrella Academy recently returned with another season, continuing the storyline after leaving fans with a major cliffhanger. Season one ended with the Hargreeves siblings escaping the incoming apocalypse by using Five's time-traveling ability. The family transported to the 1960's Dallas, each dropping at the same location in a different year. The show, inspired by the comic book series with the same name, drew parallels from the second volume of the comic, titled Dallas. However, despite the similarities, there are some big differences too, including one major plot point regarding the apocalypse.
While both the show and comic foresee the end of the world yet again, different members of the family are to blame. In the show, Vanya finds herself at the center of conflict once again. She spends most of season two in complete amnesia. While she tries to remember her identity, a family takes her in. It isn't long before her powers are discovered, and she ends up as a person of interest with federal agents. Wary of her potential ties to Russia (given her proficiency in the language and Russian name), they think her to be a spy. The intense questioning and torture become too much for her. Her powers cause an explosion in the building, triggering mass panic and a nuclear attack from the United States.
It's this chain of misunderstandings that leads to the nuclear holocaust in the show. However, events in the comic play out differently. Doomsday still comes as a result of nuclear war, but with Klaus as the catalyst, not Vanya. The difference stems from an occurrence in Dallas that was actually included in season one of the Umbrella Academy show. In the first season, professional hitmen Hazel and Cha-Cha kidnap Klaus. The partners-in-crime torture him for information. Eventually, he escapes with their case, which he accidentally uses to time travel to the Vietnam War.
However, things didn't go quite this way in the comics. This arc did draw inspiration from events in the comics, as Klaus was still kidnapped and tortured, but not until Dallas. It's in volume two that Hazel and Cha-Cha actually track him down. Along with Klaus, they also make nuclear weapons with them. When he escapes, Klaus has to deactivate the weapons with only the help of a ghost. He tries his best, per usual, but does so improperly. The weapons launch regardless and are what lead to the inevitable mass destruction.
In the end, not much differs in terms of the final result. Vanya's version does include more political nuance, whereas Klaus simply deploys the weapons and destroys the world in the progress. Either way, the Umbrella Academy does what they do best: finding a way to both stop and spark the end of the world at the same time. While a Hargreeves family member sparks doomsday in both The Umbrella Academy show and comic, it's Klaus that has to shoulder the blame for this apocalyptic event. The first one can stay on Vanya.