A boy from our world who has spent years caring for his mentally fragile mother while searching for his missing father. His discovery of a window into the abandoned city of Cittagazze brings him into Lyra's world and eventually makes him the bearer of the subtle knife - a blade capable of cutting windows between any two worlds. Quiet, self-contained, and accustomed to carrying adult burdens, he forms a partnership with Lyra that becomes the emotional centre of the trilogy.