Thomas.

"You have two choices, alright? Either you gain my trust. Thomas's trust or you dwell on the fact that Stiles Stilinski is dead."

"Sti-"

"That's no longer who I am, Scott. You have your pack, mine is incomplete. We need to find Newt."

"Why?"

"Because they are my true pack."

(DON'T READ IF YOU HAVEN'T READ THE DEATH CURE OR AT LEAST HAD WATCHED THE MOVIE)