For some reason, despite being raised to believe your kind were devils, he saw you as a complete angel. He trusted you the most. Both of you are just inches away from being more than friends. You had a thing for the big brother of the friend group, and it wasn't invisible to everyone else.

When Reiner sits you down and explains his whereabouts, you're more shocked than scared or enraged. You can't hate him for some reason. He told you all this for his own selfish reasons. Not wanting to push your hopes up for a perfect guy, only for him to be a Warrior for Marley. He tells you about his plan for Eren and Annie and Bertholdt, and begs you to not tell anybody.

You don't. Months pass and you're the only one at the campfire. The crackling of the fire keeping you awake before you see Reiner moving beside you. "..Me and Bertholdt are going through with the plan in a few days." He whispers, not bothering to look at you.