David Castañeda, who plays Diego in "The Umbrella Academy," said his character went through some positive changes in Season 2. He learned to bond with his siblings instead of trying to separate himself from them.
In Season 1, Diego was very much the aloof type. He wanted to do things his own way. He was a vigilante of sorts who refused to listen to authority nor to the advice of his siblings. Then, season 2 saw a different Diego, one whom the actor described during an interview with Daman as someone who has learned to outgrow his insecurities.
"I think the biggest change for him would be that he was able to dismantle the shadow of being number two in the Umbrella Academy and try and bring the band together rather than separating from everyone," Castañeda shared, when asked about Diego's biggest change in the installment.
The addition of Lila in "The Umbrella Academy" Season 2 also helped Diego see the importance of family. She was similar to him in a way and "Diego saw shades of himself" in her.
"Through their journey, Diego was able to open up more to his family. Just a little bit," he added.
In "The Umbrella Academy" Season 2, the Hargreeves siblings met and talked with the younger Reginald Hargreeves while trapped in 1960s Dallas. The father they knew from their present time is no different from the younger Reginald. He can still shut Diego up and bring back his stutter.
Talking about Diego and Reginald's confrontation scene in Season 2, Castañeda revealed that he wrote down questions and conversations his character would have with his father. He knew about the scene prior to filming and knew it to be an important moment for his character.
"It was one of the most important ones: It brought him back to his childhood and proved a point that sometimes you revert back to being a kid when you revisit things that you only knew as a kid," he said.
Netflix has yet to renew "The Umbrella Academy" for Season 3. If the installment is a go, then Castañeda said he wants to see Diego in a band with Vanya and Klaus just like in the comic books.