"The Umbrella Academy" showrunner Steve Blackman already has a story in mind if Netflix renews the show for Season 3 and it involves the introduction of the Sparrow Academy.
The appearance of the Sparrow Academy at the end of Season 2 was an introduction in itself for this other group of people with superhuman powers. With the first two seasons putting the spotlight on the Hargreeves siblings, Season 3 is likely going to shift focus to the members of the Sparrow Academy.
To recap, "The Umbrella Academy" Season 2 ended with yet another burning question. First, what happened to Ben? Just when the Hargreeves siblings thought they lost him forever (he is technically dead since he is already a ghost), they find him back in their time in the flesh and very much different. Whereas Ben from Seasons 1 and 2 was compassionate, kind, and emphatic, the cliffhanger teased at a whole different person in Season 3.
Ben appears to be vulgar, as teased by the question he threw at the Hargreeves patriarch, who is also still alive: "who the hell are these a--holes?" The cliffhanger hinted that Ben is the leader of the Sparrow Academy.
Interestingly, the finale also ended at a similar timeline with the third installment of Gerard Way's "The Umbrella Academy" comics, "Hotel Oblivion." Although in the comics, the leader of the Sparrow Academy is a blonde male with super strength. He also calls himself Number One, same with Luther's designation.
"It was interesting because I had a similar idea I wanted to do early on in the season, and then Gerard said, 'well, look, I'm going this direction with the graphic novel.' It was perfect, everybody thought, 'great, we want the same thing,'" Blackman told Entertainment Weekly of the Sparrow Academy's appearance in the Season 2 finale adding, "So Gerard sort of walked me through what he wanted to do with the characters they call the Sparrow Academy. I thought that was a great launching point."
Blackman said that they "already have the big plan for season 3," when asked for a potential storyline for the installment. If Netflix renews "The Umbrella Academy," he knows exactly what he can do with the Hargreeves family from Seasons 1 and 2 and the new family introduced in the cliffhanger.