HarperCollins Children's Books has bought the concluding parts to Derek Landy's Skulduggery Pleasant series, signing a deal for books seven, eight and nine.
Editorial director Nick Lake bought UK and Commonwealth rights from Michelle Kass. Since the first book was published in 2007, HarperCollins said it has sold more than two million copies worldwide.
Lake said: "I've worked with Derek since the first book, and I'm so thrilled we're continuing the journey! His inventiveness and sparkling dialogue just get better and better, while the world he created in book one has deepened and expanded in ways that have inspired an entire 'minion army' of fans.
"Those fans will be blown away by this final trilogy, too: not only will we finally encounter the Big Bad, but we'll also see Valkyrie come into her ultimate destiny . . ."
Publication dates for the books have yet to be confirmed.