Introduced as a 12-year-old boy, he meets and befriends Lyra in the world of Cittàgazze and teams up with her in order to uncover the mysteries of Dust and the disappearance of his father many years previously.
Will is quieter than Lyra, he is serious and courteous, he has a strong sense of morality (even paying for food and clothes taken from the empty city of Cittàgazze) and is very self-assured, always standing up for himself and his friends and refusing to be spoken down to.
However, towards the end of the novel, his dæmon is touched (described as a very intimate and usually forbidden action) by Lyra and she settles as a large cat with lustrous and subtle-coloured fur.
It is this power that allows her and Pantalaimon to run away from Will and Lyra, having been rescued, in order to punish the children for abandoning them when they entered the Land of the Dead.
At the beginning of The Subtle Knife, Will is trying to discover the truth behind his father's disappearance and searches his house for a box of his mother's letters, which may contain a clue to his whereabouts.
He heads to Oxford so that he can talk to his father's lawyer and while looking for somewhere to sleep that night, he discovers an interdimensional window leading to the world of Cittàgazze.
He explores the mysterious city and finds it completely empty of people – except for a girl about his own age called Lyra, who seems at first to be selfish and haughty.
Will goes back and confronts Sir Charles but is told he will only return the alethiometer in exchange for the Subtle Knife, located in the Torre degli Angeli, a stone tower in Cittàgazze.
Sir Charles is unable to retrieve the knife himself due to the Spectres which infest Cittàgazze and feed on the consciousness of adults.
However, the very next morning they are attacked by a group of Cittàgazze children who are furious at them for stealing the knife, led by the younger brother and sister of the man who tried to take it for himself.
Lyra then tells Will about a dream she had during her long sleep in which she talked to her old friend Roger (whom she accidentally led to his death at the end of Northern Lights), whose soul is now trapped in the World of the Dead.
Lyra finds Roger's ghost and apologises before Will cuts a window back out to the world, allowing the billions of souls to be released.
A group of highly developed animals approach them and carry them back to their village where Lyra's friend Mary Malone, a physicist from Will's world, is waiting among the Mulefa.
When they stop to eat, Lyra feeds him a piece of fruit that was given to them by Mary (a reference to the Fall), and they realise that they have fallen in love with each other.
In the 2013 edition of The Amber Spyglass released in the UK, the post-script Lantern Slides section reveals that Will later becomes a medical student and eventually a doctor in his world.
[2] In the unabridged audio books, Will's role is read by Steven Webb in The Subtle Knife and by Peter England in The Amber Spyglass,[3] while in the BBC's dramatisation he was played by Daniel Anthony.