So, alphainthesheets, here is my thinking.
With Deaton and Talia, we have love unrequited. Pining, angst, romance in the grandest romantic tradition. Her loss fuels his manpain for years to come, but before that, even before the fire, she wasn’t his, you know. She was her own, always, but she was also someone else’s. She’d been promised the son of a neighboring pack early, so early, before he ever met her, and she mated that wolf boy. It was fine though. He could be her Emissary. He could still be close. Even now, he feels her presence through Derek and Cora, through Scott, Hale power running through his veins. Even now he smells her sometimes, before the scent of charred wood and decay replaces the sweet honeysuckle of her.
Kali and Julia were different. From the time Julia had joined the pack, everyone knew there was something there. Something… strong. Ennis warned her, told her Julia was too smart, too sweet. There was something wrong with a woman that looked at Kali like she could be predator and prey at the same time. Kali didn’t listen. They met at the New Moon, when they could both be sure the hunger was theirs alone. They fought in front of the pack; Kali was too headstrong to listen to Julia’s advice, and Julia was always, always right. Still, in the wee hours when they were alone together, those violent clashes of spirit were whittled into something sharper, more dire. When Deucalion made his demand, Kali did what she had to. She didn’t realize that in killing Julia, she was killing herself as well. Not until it was too late. Love, lost.
Stiles has always been Scott’s safe place. Even when the influence of Peter’s Alpha insanity was thrilling through his veins, Stiles had been the one he turned to, because he knew, somehow, that Stiles would help. Would fix it. Would love him anyway. Stiles went to Deaton, asked what he could do to help, to make it easier on his best friend.
“There’s something you can do, if you are willing to work,” Deaton said, face neutral.
“Anything. I’ll do anything."
"It will tie you to him, Stiles. It will connect you like nothing else can. You’ll never be rid of him, even -” he stopped for breath. “Even after death."
Stiles just smiled. "When do we start?"
Every time Scott has fallen, Stiles has been there with him, even if all he could do was throw himself on the ground as well. It’s not a surprise when they fall into one another instead.
"Always mine, aren’t you Stiles?” Scott asks, late, in the woods on a full moon. They’ve survived, again, persisting in the face of mortal danger as if it is their sole reason for being.
“Always my Alpha. You’re mine, Scott,” Stiles says back. They do not notice if anyone hears. It does not matter.