Reader characterization is from We Are Not Soldiers in Book 1

Tony,

I'm glad you're back at the compound, I don't like the idea of you rattling around a mansion by yourself. We all need family. The Avengers are yours, maybe more so than mine. I've been on my own since I was 18. I never really fit in anywhere – even in the Army. My faith is in people, I guess. Individuals. And I'm happy to say for the most part, they haven't let me down. Which is why I can't let them down either. Locks can be replaced, but – maybe they shouldn't. I know I hurt you Tony. I guess I thought – by not telling you about your parents I was sparing you, but... I can see now I was really sparing myself. I'm sorry. Hopefully one day you can understand. I wish we agreed on the Accords, I really do. I know you were only doing what you believe in, and that's all any of us can do, it's all any of us should. So no matter what, I promise if you — if you need us. If you need me, I'll be there.

Steve

It was a stupid bet that brought you to this moment, that brought you to a letter in Tony's desk that you were never meant to see. Steve and Tony had gotten caught up in some ridiculous competition yet again, and this time the victor would get Tony's office, which was three-times bigger than the one Steve had been stuck with since the two of you moved back into the compound after a few years away. For the last week you had heard nothing but whines from your brother about how Steve had won by cheating, and endless chides and gloating from Steve as to how easy it was to beat him.

The levity of the entire situation quickly faded away as you read the words on the crumpled paper that you had found at the back of one of the desk drawers, blinking away your confusion at what it was that you had actually found. You had read it several times before finally deciding that the best way to the bottom of it was straight to the source.

"Hey, Steve?"

"Yeah, doll?" he called back from down the hall.

"Could you come here for a minute?"

The heavy footsteps heading your way began immediately, and when he arrived in the doorway, his arms were filled with nearly every belonging that he had stored in his office. Tony's room was nowhere near ready for him to move in yet, so he found an empty corner to set everything down, returning to stand behind you with a gentle rub of your neck as he looked over your shoulder at what you held in your hands for him. "Where...where did you get that?" he stammered quietly. "I thought he um, threw that away."

"What does that mean, 'by not telling you about your parents I was sparing you'?"

"Nothing, (Y/N), it's old news," he dodged, reaching out to take the letter from your hands, but you quickly evaded him. "Seriously, we've moved on."

"Tony!"

"(Y/N), come on, we don't have to bring him into-"

"What the hell was that?" Tony ran in only seconds later, his eyes wide with fear. "Who's getting murdered?"

You pushed up from the chair with a grunt and a shove to tip Steve back a few steps so that you could get to Tony without him trying to stop you, rushing forward with the letter in hand. "Tony, what is this? Steve won't tell me where this came from, and he's acting shady about it."

Tony took the letter and immediately straightened his stance, clearing his throat uncomfortably before doing his best to explain. He had put it away with the decision to leave it alone and to not revisit it, but now he realized that he should have just thrown it away in the first place. He didn't know why he hadn't, and he was kicking himself for having the opportunity for you to find it.

"Certain things came to light that we've since...resolved...for the most part. I didn't think it was anything that you needed to know. Everyone was getting along and I just wanted to keep it that way."

"Okay, I get that you wanted to play peacekeeper," you snapped, "but what I don't get is what he was hiding from you that hurt you so much to make him write this in the first place."

The two men exchanged hesitant glances past you with wordless communication as to whether or not they wanted to bring you into this. You never knew Howard and Maria, and though you were of the same DNA, they weren't really your parents in the way that they were to Tony. Your only tie to the situation was through your brother, and even he didn't know if it was worth the upset that the knowledge would potentially cause between you and Steve.

"Sweetheart, trust me, you don't need to know," Tony replied calmly, trying to diffuse the situation. "If you did, I would have told you. It's not worth getting upset about. Bucky and I worked it out..." he stopped, his voice fading as he realized his error, "I mean..."

"Bucky!"

You ripped the letter from Tony's hands as you bolted through the door and towards the common room with both men following closely behind. The silence that your friend had been trying to find was now all but ruined, setting his book aside and standing in surprise when you burst into the room and charged towards him with the paper thrust out for him to take.

"Jesus, (Y/N), you trying to give me a heart attack?"

"Bucky, what is this?" you demanded. "I'm only going to ask you once, and don't you dare lie to me. What was Steve hiding?"

He opened the letter with a glance to Steve and Tony, quickly reading its contents out of fear that you were going to start yelling at him again. "(Y/N)-"

"Now, Buck."

"Okay, I'll tell you, but you have to promise me that you'll stay calm."

You nodded eagerly and waited, jumping slightly at the feeling of Steve's hands on your shoulders again as he took his place behind you. "I promise."

"I killed them."

"Oh," you exhaled heavily, your body responding to the weight of his words, "oh my god. Okay...that's...okay, I don't..." You stumbled over your words that came from a shocked mind and an inability to put together a clear thought, much less a coherent sentence. Every option that you had imagined this to be paled in comparison to the truth that you had just been given. The emotions shifted in the room and bombarded you, from Bucky's regret and Steve's anxiety to Tony's remorse and pain, all of them striking at once. You wavered and tipped slightly as a wave of dizziness struck from the intensity, and Steve's arms were immediately around you to keep you steady.

"Hey, woah, let's sit you down."

"All of you? You all kept this from me?" you asked softly. "I understand why you would, Buck, and maybe even Tony, but Steve? After everything?"

"I didn't think you needed to know. I wanted to protect you from all of this."

"Would you guys stop using that goddamn excuse!" you finally snapped. "You treat me like I'm breakable and can't handle all of the things that go on around here! Don't you think that it's harder for me to hear now, knowing that you hid it from me, rather than just finding out at the time?"

The three men were visibly uncomfortable with the raise in your tone and from the anger that was directed at them. They looked to each other, knowing that you were right, but at a loss for what to say that would convey how sorry they were now feeling, even for something that had happened so long ago.

"You're right, sweetheart," Tony finally offered, "you're right. You've handled a hell of a lot more than most of us, and we were wrong to think that you couldn't handle this. I'm sorry."

"Me too," Bucky and Steve readily agreed in unison. "Well...maybe more me," Bucky added, "because I'm the one who did it and all."

"Subtle, Buck, real subtle," Steve groaned, leaning to rest his head in his hands, exasperated. "Let's just say that we're all sorry so we can move on, is that alright?"

"Is that all?" you asked quietly. "Is there anything else that I should know?"

Tony stepped up uncharacteristically meekly behind Steve, his hands nervously pushed into his pockets as he bounced on his heels. He wasn't sure if now was the time to add his secret into the mix, but now was likely to be as good of a time as any. "Well," he began with a quiet cough, "there is one thing. I never told you that it was me who raided your makeup last week. It was for Halloween and Rhodey and I went to a party as Ebony and Ivory and I wasn't Ivory enough."

"No, Tony...that's not..." you stuttered in disbelief, your eyes as wide as both Steve's and Bucky's while they looked on with similar shock, "that's not exactly where I was going with that. But you know, now that you've brought it up," you smiled coyly, "we're gonna need to see some pictures."