'Stoick' the Vast is the Chief of Berk and father to Hiccup. Despite holding such important positions, Stoick is not a major part of gameplay. He can be found in front of the Great Hall on Berk, where he aides players in a few quests as well as giving some quests of his own.
Stoick serves as the chat filter's warning message inside of Thunder Run Racing.
Stoick used to always follow Viking tradition, which included killing dragons. However, after Hiccup defeated the Red Death in the first How To Train Your Dragon movie, Stoick began to open up to his son's new way of thinking. At one point in the Riders of Berk TV series, Stoick gains his own dragon, a Thunderdrum named Thornado. As the Dragons series continues, Stoick releases Thornado so that his dragon can protect other Thunderdrums. Even later in the series, Stoick bonds to a new dragon, a Rumblehorn who he calls Skullcrusher.
While School of Dragons is not canon, it fits in somewhere between the TV series and the second movie. To that end, the events at the end of How To Train Your Dragon 2 have not happened within the game world. Additionally, there is no mention of Stoick's Thornado except in A Sickly Dragon but at least one stable mission mentions Skullcrusher.
Version 2.0 of the game (June 26th 2016) bring Valka to the game, and Stoick is then removed. His quests have been distribuited to other characters.