Actor Ian McShane was cast in the reboot as Hellboy's adopted father, Professor Broom. McShane recently spoke with Fandom and revealed that Broom and Hellboy will have a much different relationship than in the previous films, and a lot of that comes from where the movie chooses to begin their story.
“You don’t start with the birth of Hellboy… but the relationship between [Hellboy and Broom] is quite crusty. Does he trust his father? [Hellboy asks], ‘Why didn’t you kill me? I’m a monster.’ It’s a little bit of a psychological battle against Hellboy.