In December 2010, DreamWorks CEO Jeffrey Katzenberg confirmed that there would also be a third film in the series: "How To Train Your Dragon is at least three: maybe more, but we know there are at least three chapters to that story."
Dean DeBlois, the writer and director of the second and the third film, said that How to Train Your Dragon 2 is being intentionally designed as the second act of the trilogy: "There are certain characters and situations that come into play in the second film that will become much more crucial to the story by the third."
DeBlois explained the release date shift: "It's just that these movies take three years. I think it was a little ambitious to say 2016 (laughs). As is normally the case, they kind of throw darts out into the future and wherever they land they call that a release date until we start talking about it in practical terms, and then it's like, 'Uh yeah that's not enough time. So knowing that they take three years from this moment, from outlining and writing the screenplay through to the final lighting of it, it's just a process of building models and doing tests and animating, storyboarding, the whole thing just adds up to about three years."
Jay Baruchel as Hiccup Horrendous Haddock III: companion of Toothless, a Night Fury.
Producer Bonnie Arnold declared that Hiccup's appeal emerges from Baruchel's voice acting and the character's mannerisms making him a "slightly offbeat character."
Gerard Butler as Stoick the Vast, the chieftain of the Viking tribe and Hiccup's father. A fierce, immensely strong and utterly fearless, warrior.
Director Chris Sanders described Stoick as "representing everything that's Viking", and thus a very important character in how he intimidates his son Hiccup. Butler considered that "half my career led me into playing a role like this," particularly Beowulf & Grendel, which is set in the Viking age, and was trying to avoid depicting Stoick as villainous, instead aiming for "a character that we can all identify, he's not just big and tough, also vulnerable."
Cate Blanchett as Valka.
Valka is the wife of Stoick the Vast and mother of Hiccup. She was abducted by dragons when Hiccup was still a baby. She does not trust people because of her love for dragons.
Jonah Hill as Snotlout Jorgenson, one of Hiccup's dragon-training classmates. Snotlout is brash, overconfident, and fairly unintelligent, but reliable.
Kristen Wiig as Ruffnut Thorston, twin of Tuffnut. A pair of quarrelsome twins.
Christopher Mintz-Plasse as Fishlegs Ingerman: an enthusiastic youth, knowledgeable in dragon lore narrated role-playing game terms.
Bonnie Arnold declared Mintz-Plasse's voice made them immediately think of Fishlegs, as the character's big frame needed something to contrast, and the actor's "squeaky, small voice" was perfect to complement a "dragon nerd".
America Ferrera as Astrid Hofferson, Hiccup's fellow-student.
DreamWorks had long been interested in having Ferrera voicing one of their movies and, once invited, the actress picked up Cressida Cowell's book, which made her accept the job. Bonnie Arnold complimented how Ferrera "has a strong voice, but also a lot of heart in it" that helped make Astrid sympathetic even as she continued being rough to Hiccup.
Djimon Hounsou as Drago.
T.J. Miller as Tuffnut Thorston, twin of Ruffnut Thorston. A pair of quarrelsome twins.
Craig Ferguson as Gobber the Belch: blacksmith, a close friend of Stoick's, and training master of the young warriors. He is the mediator between Hiccup and Stoick. He is missing his right foot and his left hand, the latter of which he has replaced with a variety of specialized prosthetics.
Director Dean Deblois said Gobber's characterization drew a lot from how Ferguson's comedic routine "takes a really dark situation and phrases it in a way there's always a punchline."