You give them “Where’s the angel?” “I’m not leaving here without you.” “Where the hell are you man?” “I know you’re in there, We’re family, we need you. I need you.”
You let it simmer.
You give them face-cradling, death of a loved one. You give them “I can’t let you do this.” “Nobody wants him here more than I do.” You give them “He’s in love…” “Don’t lose it over one man.” “You gave up an entire army for one guy.” “It was all about saving one human, right?”
You let it simmer.
Then you pile it on.
You give them “You can’t stand the fact that he’s mine.” “Dean Winchester completes me.” “Our future” “We’ve done extraordinary things to triplets.” “all of this that’s bloomed between us never ends.” “I want you to kill for us.” “I think you don’t know what you want.” “Pick a bloody side!” “they’re good for a fling, but they’re not relationship material.” “We’re done.” ”Your misadventure with the older Winchester was quite the topic of speculation.” “you run off with your boy toy, Dean Winchester”
You let it simmer.
You bring in the idea of “shipping.” You give them three variations of the word “Destiel” to ponder on and a love song from “Cas” to match. “They’re a couple in real life.”
You let it simmer.
You give them “Bromance” Let them sit with the idea. Was it bromance? Or could they leave the “b” out of it?
You give them “There is no us.” You give them Dean choosing Castiel. You place Castiel in the spot of Cain’s romantic interest.
He looks surprised that he was even thinking about it in the first place.
He looks like he just realised the biggest, most simple truth he’s ever known. Like it’s something so deep and all-consumming that he managed to not notice it for some time, but that’s only because it was there all along. And that makes sense. Because his rebellion from Heaven began with this. This was his biggest motivation to walk into everything that happened afterwards. And it will break through his very nature, because it’s bigger. Stronger. More important. It was the first thing Castiel had ever wanted for his own.
Like everyone else, I’m just waiting for him to say “I need you too”.
A character has something he believes in more than anything. A person he has sworn to protect, an ideal he’s sworn to uphold. He might have spoken that vow in a sacred ceremony, or simply made a decision in the silence of his heart, it doesn’t matter. What matters it that no matter what, he will not break it.
And that, essentially, is the core of this trope – a character-trait so important to the character that he will break free of outside control or amnesia to keep it.
Simply having a vow will not suffice, if it has not been ‘tested’ in this manner.