The hook of Underworld was vampires fighting werewolves. Now the third film, a prequel currently known as Underworld: Rise of the Lycans, gives the werewolves the lead. Producer Tom Rosenberg explained the differences in werewolf style to the full on Underworld style.

"It's more like the flashback scenes in 2," said Rosenberg. "Remember in the first one Michael Sheen's wife Sonia was killed by Bill Nighy, by Viktor, and that was his daughter?  That was the back-story for Michael Sheen.  Obviously this is how they meet and Michael Sheen becomes the leader of the werewolves.  This is told from the werewolf's perspective, not the vampire's.  It's their story and their battle with Viktor."

Rosenberg assured that this departure was consistent in the original plans for an Underworld trilogy, and that a fourth film with Kate Beckinsale and Scott Speedman is still possible.

"I think it's the strongest story that we've put together of the three.  I think it's really terrific.  I think it leads to a fourth.  When we did the first Underworld, we imagined three: the first one, a sequel and then a prequel.  The third is a prequel, so the fourth would carry on where Kate and Scott Speedman left off after 2, so I think this is going to be terrific."