The X-Files. Though the character was originally created back in 1994, it was the 2004 movie that truly turned Hellboy into a household name.
While del Toro's two Hellboy movies were critical darlings that proved to be reasonably successful at the box office (earning a combined $260 worldwide), they didn't quite reach the blockbuster ambitions for which the film studios were surely hoping. Star Ron Perlman and director del Toro had hoped to return to the franchise with a third Hellboy movie, but those hopes were ultimately dashed with the development of the 2019 reboot.
Mike Mignola had co-written drafts of the Hellboy 3 script, and went on to consult with the reboot once it was decided to take the franchise in a new direction. Screen Rant spoke to Hellboy creator Mignola about his work on all the Hellboy movies, including the scrapped del Toro sequel, which was ultimately Serenity, and The X-Files (before the comics were made non-canon once the series was brought back for two additional seasons on the Fox network). Alas, this was not to be for Hellboy, as Mignola explains:
"I think del Toro mentioned it to me once, and I said no. I think, let the comics be the comics. Comics are confusing enough for people. Let's not have two different versions of the Hellboy comic out there. My vote would be (to say) no."
Even if fans may clamor for a proper conclusion to the Perlman/del Toro saga, Mignola has a point. Comics can get Crisis on Infinite Earths. That type of storytelling doesn't appeal to Mignola, who would rather have the comics maintain their own continuity, separate from the films.
That being said, there were a pair of straight-to-DVD animated films set in the universe of the del Toro films, which featured much of the cast from the movies reprising their roles. Perhaps such an avenue could be the ultimate fate of Hellboy III. Then again, considering how poorly the Hellboy reboot performed at the box office, maybe the series will be un-rebooted, and Hellboy III might actually have a chance at being made, after all! It's extremely unlikely, but stranger things have happened in Hollywood.
