The books—"MPH" and "Starlight," respectively—are being published by Image Comics this year.
They're the latest in his efforts to not just exert creative control over characters and concepts he's created, but to expand storytelling in the pages of comics with a more contemporary vibe and with real-world influences, too, under his Millarworld umbrella.
It's integral to his drive to create modern characters for a modern generation raised on classic tales but yearning for what he called "21st century" heroes.
"I think pop culture atrophies if it doesn't move on," he said of his desire to advance a new breed of heroes while acknowledging and paying homage to those who came before like Batman and Spider-Man or Wonder Woman and Black Widow.
"DC Comics created all their main characters—Superman, Batman, Wonder Woman, Flash, Green Lantern—between about 1938 and 1942," he said. "All the major Marvel characters, all the ones we really understand, were created 10 years before I was born, in the early 1960s.
Yes, they have a resonance that remains strong 75 and 50 years after their creation he said, but readers want new characters, too.
"Each generation has their own universe of heroes like this and I just thought, 'My God, there's a gigantic gap in the market," he said. "A whole wave of contemporary superheroes and 'Kick-Ass' was the first step in that direction."
His "Kick-Ass" series, which is in its third outing and has yielded two successful movies, along with associated merchandise, has given Millar a stepping stone.
"MPH," a five-issue miniseries due out May 21 and illustrated by artist Duncan Fegredo, is about four teens from Detroit who stumble upon a batch of illicit pills that gives them the power to move at light speed for seven days.
It is, Millar said, as if your neighbor down the street suddenly manifested the powers of Mercury.
"This guy who is looking for a new life and this pill is his way out of it," he said of the story, which examines whether having such gifts will result in ruin or something more noble. "The four most powerful people in the country are these four teenagers."
That book, along with "Starlight," a space opera serial in the Flash Gordon or Buck Rogers vein that sees the protagonist dealing with retirement, is serving as a gateway to Millarworld's upcoming titles.
"I liked the idea of having an entry-level book. It won't initially feel like it's connected, but it will all eventually interconnect," he said of the book illustrated by Goran Parlov and due out March 5. "I have nine titles planned in a three year timeframe here. This opens the door to those."
Ultimately, the creator of "Civil War" and writer of "Swamp Thing" and "The Ultimates" views his new works as an opportunity to seed new readers for today and beyond.
"I really do believe that the public is very, very tuned into the idea of heroes created in the 21st century," Millar said. "I'm devoting the next few years of my life to trying to do the 21st century version of the Marvel universe."
Moore reported from Philadelphia. Follow him on Twitter at www.twitter.com/mattmooreap