Medical professional (sometime in his future)
William "Will" Parry (b. 1985) was a twelve-year old boy who was the temporary bearer of Æsahættr. He is the sole child of John Parry, an explorer, and Elaine Parry. During his first months of life, his father left on an expedition to the Arctic, and did not return. Will spent his childhood caring for his mother.
Will eventually entrusted his mother's safety to a former piano teacher, Mrs. Cooper, after several agents began to turn up and question her about her husband. After contingently murdering one of the agents, he escaped and wandered into the city of Cittàgazze, in an entirely different world, where he met Lyra Silvertongue, a girl from yet another world, whom he would inevitably fall in love with.
Will has been described as having straight black eyebrows, dark hair, a strong, jutting jaw, a muscular build for his age, and often a passionate ferocity in his eyes.
Will Parry is the son of John Parry, an explorer, and of Elaine Parry, a woman who suffers from apparent mental problems including obsessive-compulsive disorder and paranoia. Will fails to remember his father, a former Royal Marine, who has not been heard of since he vanished on an expedition to the Arctic, and who we later learn has wandered into another world and is unable to find his way back.
Will must take care of his mother, due to her ailment, until they are accosted by several agents of an unknown interest. He decides that he must leave her with his former piano teacher, Mrs. Cooper, and himself flees, accidentally killing one of the agents as he makes his escape. He accidentally finds a passageway to the city of Cittàgazze in another world, in which he meets Lyra Belacqua. Lyra's alethiometer tells her that he is a murderer, possibly foreshadowing the consequence of his acquisition of the subtle knife. In gaining the knife, he also loses the littlest and ring fingers of his left hand.
Will's attachment to Lyra deepens, until he greets her with such gestures of endearment as he has learned in his journey. These include the placement of food in the cherished one's mouth, the French kiss, and close embraces. Needless to say; they fall in true love with each other. Will also plays a pivotal role in the war that Lord Asriel and the angels wage against The Authority.
After being separated from Will during the journey to the world of the dead, his soul becomes visible as a dæmon. Prior to reuniting with Will, she is named Kirjava by Serafina Pekkala. Kirjava's name is Finnish for "multi-coloured". At the end of the trilogy, Kirjava settles in the shape of a large, coloured cat.