Characters: The Secret of Kells
Voiced by: Evan McGuire (child); Micheal McGrath (adult)
- Friend to All Living Things: There's the whole goose scene where he's introduced, where he's very gentle with it once it's caught. He also quickly makes friends with Pangur Ban the cat and later Aisling, a forest sprite.
- Hes All Grown Up: And has completed the Book of Kells.
- The Hero
- Innocent Blue Eyes: To show his naiveté (especially from his uncle) and his curious nature.
- Nice Guy: Brendan is a polite, honest, and respectful young boy.
- Red-Headed Hero
- Title Character: In the alternative title: "Brendan and the Secret of Kells".
Voiced by: Christen Mooney
- Breakout Character: She pretty much stole the audience even with the limited screentime she had. Aisling even found her way into Empire's list of 50 best animated movie characters. She also had the honor of going to the Oscars in 2010 when the film was nominated for Best Animated Feature.
- The Fair Folk: She's nicer than most examples, but she still isn't above siccing her wolves on people who trespass in the forest, which she considers hers.
- Friend to All Living Things: She states that the forest is hers, and it's implied that she can communicate with everything in it. She later forms a close friendship with both Brendan and Pangur Ban.
- Jerk with a Heart of Gold: She's more than a bit prickly towards Brendan at first, initially setting her wolves on him and then demanding that he leave her forest, but she soon warms up to him and becomes quite loyal to him afterwards.
- Morphic Resonance: Whenever she changes shape, you can tell it's her thanks to her white colouring and green eyes.
- Mystical White Hair: She has white hair and, being of The Fair Folk, is definitely magical. According to the tie-in comic, it's a racial trait of all her people.
- Rapunzel Hair: That reaches all the way to her ankles.
- Really 700 Years Old: She states outright in the opening that she's "lived through many ages", and years later, when Brendan is an adult, she looks exactly the same as she did when he was a child.
- Super Strength: This petite girl can lift and/or push down statues with ease.
- Voluntary Shapeshifting: One of her abilities is being able to turn into animals. She mainly turns into a wolf, but the opening shows her as a salmon and a deer as well.
Voiced by: Brendan Glesson
- Bald of Awesome
- Cool Uncle: Averted. The Abbott isn't a horrible person, but not exactly "Mr. Warm" even to his own nephew.
- Evil Uncle: Also averted, though he is the movie's antagonist for a good portion of it.
- Jerk with a Heart of Gold: The Abbott is a stern, no-nonsense man with a stubborn disposition, but end the end he does mean well.
- Perpetual Frowner: Never see him smile once. Until Brendan's return.
- Well-Intentioned Extremist: His actions aren't ideal, but his motives are sound.
Voiced by: Mick Lally
- Cool Old Guy: A lot more warmer than the Abbott.
Voiced by: N/A
- Ambiguous Gender: Averted; it isn't clear what Pangur Ban's gender is in the film, but the novelization and Designing The Secret of Kells confirm that she's female.
- Cats Are Snarkers: Of the Silent Snarker variety.
- Defrosting Ice Cat: She really starts to warm off Brendan. Eventually, after Aidan's death, she now travels with an adult Brendan.
- The Shadow Knows: Even when transformed into a sprite by Aisling, her shadow remains that of a normal cat.