Will thinks he knows when Lyra dies.
There have been moments when he thinks he can feel her, or something close to it, through the infinitesimally small, impossibly large barrier that separates them. The first time was on the summer solstice, sitting with her on the bench across stars and space, but there have been others. The sensation is hot and cold and feels very much like catching the space between atoms that he had learned to feel with the tip of the knife, and leaves him and Kirjava aching for weeks.
He is a doctor, now, teaching medial students how to help; Mary's influence on him has turned him from the angry, hurt boy he had been into a researcher and scientist. He is in his office, Kirijava in his lap, reading a novel while waiting for any students to turn up for his office hour. They never do. The tea beside him is cold.
Kirjava notices it first, her claws pricking into his thigh. He cannot breathe with the pressure in his lungs, a sudden, sharp ache that reminds him of the separation from his daemon going into death. As quickly as it comes, it is over, and he is crying. He can't stop crying. Will has to leave the building, has to get somewhere safe and private.
His flat is cold and dark, but he doesn't mind or even notice. He curls up in bed, still dressed, Kirjava cradled close to his chest. She hasn't said a word; the shock of it has silenced her. He sleeps, hours later, out of exhaustion.
Predictably, he dreams of Lyra. Not the Lyra he had known, but a grown woman, thin and slightly pinched-looking, with gold hair and sharp eyes. She visits him frequently this way, and he has always wondered if he plays as often in her dreams.
"I'll drift about forever, all my atoms, until I find you again," says Lyra. He tries to touch her, but she is dissolving before him.
When he wakes, Will finds, to his surprise, that there is a peace in emptiness. And perhaps now Lyra can be closer to him than she has been since they were practically children together, without the barriers between the worlds to keep them apart.