The finale of The Umbrella Academy saw Sir Reginald Hargreeves stop Allison from stepping on one of the Hotel Oblivion stars, suggesting several things about his grander schemes for the series. Through season 3, the Hotel Oblivion was steadily revealed to be built in a location that would allow Reginald to potentially reset the timeline and rescue his former home world. Reggie was adamant that he needed at least seven of his adopted children to complete his Oblivion project, explaining why both The Sparrows and Umbrellas had seven members.
As such, it makes sense as to why he left Allison out of the direct carrying out of his scheme, given the pair had previously agreed to work together. Allison's motivation to recover her daughter and husband from their respective lost timelines led her to brutally turn against her siblings in order to secretly have a chance to reset the timeline. This all may explain why Reginald insisted she didn't step on one of the Hotel Oblivion stars.SCREENRANT VIDEO OF THE DAY
Related: So, Reginald Only Getting Seven Umbrellas and Sparrows Was On Purpose?
Initially, it seems as if Allison is no longer needed solely because Klaus resurrected himself and joined the group in their final hours. With the group now at eight, Allison was the odd woman out, and thus not needed to stand on one of the Hotel Oblivion's 7 stars. However, Allison's picture-perfect season 3 ending in The Umbrella Academy suggests that she and Reggie had a more intricate plan than what was let on. Unlike her siblings, who were transported to the remnants of the Hotel Oblivion, she was reunited with her daughter and her alternate 1960s timeline husband during the 'reset.' This unlikely outcome hints that she and Reggie skewed this new alternate timeline at the end of The Umbrella Academy season 3, explaining why he may have avoided having her take direct part in stepping on the stars themselves - as those who did seemingly show up in this new world later than Reginald and Allison themselves.
Allison's Agreement With Reggie in Umbrella Academy Season 3 Explained
After Luther and Sloane's wedding, Number Five overheard Reggie talking with a mystery person, establishing some sort of deal. The mystery person is revealed later on to be none other than Allison. Many of the motions set into play were Reggie's doing in order to reunite with the mysterious Abigail Hargreeves. His need for seven individuals explained why he essentially gave up on the Umbrellas in season 1 after the death of the original Ben. Seeing his failure, he adopted seven new children in the Sparrow timeline to retry his mission.
By The Umbrella Academy season 3 ending, Reggie and Allison are so desperate to gain what they have lost that their striking a deal does make sense. After her falling out with Viktor and her mistreatment of her other siblings, Allison is seemingly willing to do anything to change things. While the explicit details of their deal are not revealed, it is obvious it involved reuniting Allison with her husband and daughter, as the season closes with their somewhat vague reunion. With Allison on board, Reggie is effectively able to finally get the rest of the team to help him defeat the guardians and reset the universe.
Allison's season 3 ending makes the timeline of this new world even more worrying, as pulling her husband from the 1960s would be sure to have some future consequences, suggesting Reginald and Allison entirely changed all of the timeline they are now in - perhaps explaining why Reginald appears to have an industry empire, and why there are now two Bens around. This new timeline also appears to have removed the powers of both the Umbrella and Sparrow Academy members, and reverted them back to their original forms, which also supports the idea that massive changes outside of Reginald's world and Allison's family have happened. It is unknown if this power removal also applies to Allison, who still displayed her injuries sustained before the reset. If she has retained her powers, she would be very formidable if her siblings tried to undo the reset in The Umbrella Academy season 4.