SCI FI Wire spoke with Hellboy star Ron Perlman, who revealed the sequel’s working title is Hellboy 2: The Golden Army:
“I think that that’s an invention based on a number of different things that have appeared in other comic books,” Perlman said of the title in an interview while promoting the upcoming television miniseries Stephen King’s Desperation.”"But basically the idea for [Hellboy 2] was something that was hatched by [Hellboy comic-book creator] Mike Mignola, with [Hellboy writer-director] Guillermo [del Toro] sitting alongside of him. And then Guillermo, of course, did all of the writing. But, you know, the story was Mignola.”
Check out more of the interview at the link above.