Eleven years ago, Eoin Colfer’s Artemis Fowl first introduced readers to the eponymous, 12-year-old criminal mastermind, and to fairy police captain Holly Short. Kids were quick to embrace these and the novel’s other characters, and Colfer added seven more books to the series, whose in-print tally in the U.S. alone has swelled to 13 million copies. On July 10, Disney-Hyperion released The Last Guardian, the eighth and final installment of the series, in which Artemis calls on Holly to help him defeat his arch rival, the evil pixie Opal Koboi. The publisher launched the novel with a million-copy first printing and an eight-city author tour, on which Colfer encountered many fans who are thrilled to have a new Artemis Fowl book to devour, but sad to see the series wrap up.

The Irish author likewise expresses mixed emotions about bidding farewell to the young hero. “For the past 12 years, at least half of the thoughts chasing themselves around my head have been about Artemis Fowl,” he says. “I have gone to sleep thinking about pixies and woken up considering elves. I have been trying to think about other things, but often catch myself developing stories for Artemis and company almost unconsciously. I think that I have not yet accepted that I am finished with Artemis. It is beginning to hit home now that I am traveling and reaching fans who are sad that the series is over. And I must admit I am feeling a little sad myself, but also happy to move on to the next projects.”

Indeed, it seems that Artemis and company are quite a persistent bunch. Colfer originally envisioned Artemis Fowl as a trilogy, but realized along the way that that was not to be. “I tried to stop after three, but I kept having ideas that I felt were too strong to ignore,” he recalls. “Twice I began writing other books only to realize after awhile that they really were Artemis stories. I decided that I could only write a book about Artemis if the story was strong enough, so I planned one at a time. After eight, I concluded it was time to move on.”

Also sharing the bittersweet experience of the series finale is Colfer’s editor, Stephanie Lurie, editorial director of Disney-Hyperion. Reflecting on Artemis Fowl’s success, she notes, “In stark contrast to Harry Potter, Artemis is an antihero. To achieve his often nefarious goals, he relies not on a magic wand, but on his genius and on high-tech gadgets that would make James Bond drool. His friends provide the heart that Artemis seemed to lack, and Eoin also adds comic relief. The result is a very modern action adventure, and readers see Artemis grow into an upstanding citizen who puts others first. Though it’s sad that there will be no more stories, Eoin made the only decision he could. His boy is all grown up now.”

Still, Colfer admits that leaving Artemis and his cohorts behind after finishing The Last Guardian hasn’t been easy. “Artemis and his characters still haunt me, but in a friendly way, like Casper,” he says. “It will take months or even years for their ghosts to disappear from my mind.”

A Rousing Sendoff

As he’s done while promoting earlier Artemis Fowl books, Colfer on his recent tour demonstrated impressive stage presence. His “8 in 8” performance condensed the eight installments of the series into eight minutes, with Colfer sharing the stage with two fans who played the roles of Artemis and Holly at each event. “It was great fun doing the ‘8 in 8,’ ” he says. “All of the kids participating were great and we had packed venues all across the U.S. It was wonderful to meet readers who had stuck with the series since the beginning – some are married with children now.”

Fresh off the road and headed back across the Atlantic, Colfer cites several of the most memorable moments from his U.S. tour. These included performing “8 in 8” at a packed hall at San Diego Comic Con, with Jake Short form Disney Channel’s ANT Farm playing the role of Artemis; and an event at Provo City Library in Utah, where library staffers showed up dressed as fairies. And the tour’s crowning event was the last stop. “I think my absolutely favorite moment,” Colfer recalls, “was the swell of emotion that rose up in the crowd at St. Louis County Library, where we said goodbye to Artemis for the last time.”

Carrie Robb, the Missouri library’s programing coordinator, agrees that Colfer’s July 21 performance before an audience of 350 was memorable – and moving. “This is the fourth time we’ve hosted Eoin, and he always does something a little different and makes a spectacular night of it,” she says. “He is probably one of the most hilarious authors we’ve ever had here – he’s a comic genius. With this ‘8 in 8’ performance, he tied the whole Artemis Fowl series together for kids. A lot of the kids present had grown up with Artemis and wanted to say goodbye to this favorite character. When Eoin announced that this was the last-ever U.S. celebration of Artemis, he was obviously emotional, and the audience felt the same way.”

Happily for fans, they’ve not seen the last of Artemis Fowl. A film adaptation of the first two books has been in the works for several years and, according to Colfer, “seems to be moving forward apace. We have a director attached and are a few drafts away from a brilliant script.”

Colfer’s readers will also be pleased to learn that he has been busy with new writing projects post-Artemis Fowl, with two books set to be released in 2013: a sequel to last year’s Plugged, a crime thriller for adults, and the first in a YA series called WARP, which he calls “a time travel-adventure comedy. I hope the Artemis fans will take to it.” Overlook will publish the follow-up to Plugged, tentatively titled Screwed, next May; and WARP is due from Hyperion in April.

And there are more books to come. “I have plenty of ideas all fighting for supremacy in my head,” Colfer says. “I can honestly say that I have more ideas than time, so as long as people keep reading, I will keep writing. And to be honest, even if people stop reading, I will probably keep on making up stories.”

Artemis Fowl: The Last Guardian by Eoin Colfer. Disney-Hyperion, $18.99 July ISBN 978-1-4231-6161-5