Boreas is the Greek god of the North Wind and Winter. He is also one of the four seasonal wind gods that work for Aeolus, the master of all winds. He settled down in Quebec City, Canada, the oldest settlement in the North. He's the only god that we know of who does not normally speak English in North America; he speaks French instead, as it is the sole official language of the province of Quebec. His Roman counterpart is Aquilon.

Boreas appeared at his palace when Jason Grace, Piper McLean, and Leo Valdez go to him for help (because he was the closest to Camp Half Blood). He is ordered to kill the heroes, due to Aeolus' command. But Boreas first agrees to hear what the heroes are setting out to do, which is when they tell Boreas that they are on a quest to save Hera. After Boreas saw Jason's tattoo, he changes into his Roman form, Aquilon. Boreas releases them out of amusement, thinking they are bound to die, and there is no need for him to kill them.