Hearthstone

Hearth is a homeless man who befriended Magnus Chase after he lost his mother.

The Sword of Summer
Blitz wakes up Magnus one morning and tells him he should to go talk to Hearth.

After breaking into his uncle Randolph Chase's house, Magnus looks outside the office window and sees Hearth standing next to a statue of Leif Erikson. Hearth uses hand actions to try to tell Magnus to get out of the house, but it was too late as Randolph returns home and comes upon Magnus and tells him that they don't have much time and "they" are coming to kill Magnus now that he's sixteen.

Appearance
Hearth is a tall pale man with short, spiky hair so blonde it's almost white and pale grey eyes. He wears a black leather jacket, black motorcycle pants and pointy-toed shoes, and a red and white scarf.