Soulmates AU in which the red string of fate shows up when a life altering moment takes place between you and your soulmate. Like, Eren killing two grown man to save/help Mikasa kind of important. A moment that changes at least one of them.

And, you know, because this is about JeanMarco as always - these two dorks filling their gas, Marco telling him why he's a good leader and stuff and Jean watching him, shocked about what he's saying... Then he takes notice of the red string tying him to Marco and his eyes widen even more in shock, like it both made no sense and all the sense in the world. Marco doesn't even notice until he's done talking and sees Jean's reaction and his reaction is something similar to 'Oh', both because Jean was his soulmate and because that moment meant something important to Jean. And they're both so awkward, not knowing how to process this.