Kick-Ass's creator, Mark Millar, is planning a third instalment of the comic-book movie saga, but says it will be its last outing, according to the Press Association.

Millar, whose graphic novels about a teenager who decides to become a superhero despite having no superpowers form the basis of the film series, revealed that he is already working on a Kick-Ass 3 comic. His proposed movie version would see Aaron Taylor-Johnson and Chloë Grace Moretz return for one last hurrah as masked crime fighters Kick-Ass, aka Dave Lizewski, and Hit-Girl.

Kick-Ass 2: video review guardian.co.uk

"It's the conclusion of the Dave Lizewski story. I'm almost done, I've nearly finished the book," said Millar, who took a producer's role on both 2010's Kick-Ass and current sequel Kick-Ass 2. "It's the end. It's weird. My agent keeps saying to me, 'We're making a lot of money here. Let's do Kick-Ass 4 and 5.' But I said, 'No, I've got to stay true to my principles'."

Millar said the denouement would be "very logical", adding: "I want to end it where I want to end it, because when I first put this together in 2006, I had this ending and it's the very logical conclusion. To milk it beyond that either means I've got greedy or I've come up with some brilliant new idea, but it probably pretty much ends with Kick-Ass 3. I've always seen it as a trilogy."

Three years separated the release of Matthew Vaughn's Kick-Ass and the followup, which was directed by Jeff Wadlow. Millar said producers would need to move more quickly on a third outing before the saga's main stars, 16-year-old Moretz and 23-year-old Aaron Taylor-Johnson, become too old for their roles.

"I don't think we can wait that long because the youth of the characters is really important. Hit-Girl's going to be a mum in the next one if we don't hurry up," joked Millar. "I reckon if we do this one, we should try and do it in the next couple of years – it depends on schedules though because these guys are all really busy. But we need to move fast with it."

One issue could be that Kick-Ass 2 has so far failed to repeat the financial success of its predecessor, taking just $40m (£26m) worldwide so far against $96m for the first film.

More on Kick-Ass 2

• Kick-Ass 2: first-look review

• Chloë Grace Moretz on Kick-Ass 2: 'It's anti-comic book'

• Jim Carrey condemns violence in his own movie, Kick-Ass 2

