
Jem leaned closer against the chair, staring into the fire. “Better it were my hands,” he said. Will shook his head. Exhaustion was muting the edges of everything in the room, blurring the flocked wallpaper into a single mass of dark color. “No. Not your hands. You need your hands for the violin. What do I need mine for?”
If Jem dies in Clockwork Princess:
If Will dies in Clockwork Princess:
If they both die in Clockwork Princess:

“I know about parabatai,” said Magnus, his voice rising in pitch. “I’ve known parabatai so close they were almost the same person; do you know what happens, when one of them dies, to the one that’s left—”
“Jem knotted his fingers in the material of Will’s sleeve. “You are my parabatai,” he said, “You said once I could ask anything of you.”
— Clockwork Princess
“I suppose I do,” said Will, after a pause. “Not that it matters for me, but—” He
shrugged. “If love is great, then it is worth fighting for.”
“What if it is immoral somehow? Forbidden?” Jem asked.
“Forbidden? But my father’s love for my mother was forbidden, or at least against the
Law. Or do mean if she is married, or a vampire?”
“Or a married vampire.”
“Well, nevertheless,” Will said with a grin, “one should fight on. Love conquers all.”
It’s Will and Jem in the deleted pre-Clockwork Angel scene. I just hope to the angel Raziel that Will stands by his word, and fights for Tess. Just like he said he would.