Actions

Work Header

Rating:
Archive Warning:
Category:
Fandoms:
Relationships:
Characters:
Additional Tags:
Language:
English
Stats:
Published:
2025-10-30
Updated:
2025-11-29
Words:
39,002
Chapters:
24/?
Comments:
12
Kudos:
34
Bookmarks:
11
Hits:
1,684

to keep a legacy

Summary:

"ᴡʜᴏ ʟɪᴠᴇꜱ, ᴡʜᴏ ᴅɪᴇꜱ, ᴡʜᴏ ᴛᴇʟʟꜱ ᴏᴜʀ ꜱᴛᴏʀʏ?"

At a young age after loosing her mother, Sienna was adopted by the billionaire superhero Tony Stark. The young girl thought she'd lost everything and everyone, but she found a family. And maybe, just maybe, she'd find who she is, who she's meant to be, and her legacy to keep.

Disclaimer! English is not my first language so if there's something that's not well written or is confusing don't be afraid to tell me, I'd love to keep improving my writing!

Notes:

Time period-Updated:
- Iron Man 2010: chapter 1- 4 ✓
- Avengers 2012: chapter 5 - 11 ✓
- Iron Man 2013 and Captain America and The Winter Soldier 2014 mixed: 12 - 15 ✓
- Avengers Age of Ultron 2015: chapter 16- currently

Chapter Text

State of New York, USA, 2009

It had been a year since the world had met Iron Man, and Tony Stark's life had changed a lot since then. Little did he know how much change there was still left to face.

Tony had been working in some projects here and there with SHIELD, an Approved Intelligence, Espionage, Logistics and Defense System extragovermental organization. Specially since he became his new identity, the agency'd been really insistent on him becoming some kind of agent.

Of course it made sense, he was the richest man in the world, a genius and he surely had the courage to stand on business, but Tony never thought he was the kind to be a "hero".

When Nick Fury, the head of Shield, asked him specifically to meet him personally at the New York office he thought it would be about this crazy idea of his about making him a hero. Anyway, he accepted in case it would be something else since Fury was being really persistent about it.

He pulled up out of the car in front of the building and said goodbye to Happy, his assistant and dear friend, who drove him there.

At the door there was an undercover agent who would take him to the occult part of the building, where the NY SHIELD base was located at the time. He made his way to the main office, where Nick and his left hand, Maria Hill, where waiting for him.

He entered ready to decline the same old offer and maybe hand some help somehow, but he wasn't ready at all for what was about to happen in there.

"Fury, Agent Hill. So what do I owe this pleasure to?" Tony said taking place in the oposite side of the desk facing them directly.

"Tony, we have something really serious to discuss with you, so I am gonna ask for you to let your jokes aside on this, because I think you might want to take this with philosophy." Said Maria, setting the scene and making Tony move uncomfortably in his chair due to the frankness in the words of the agent.

"Gisele Soulard. Do you remember her? You two had some relationship. She used to work with us but years ago we lost track of her." Nick started to explain.

"Yeah I do, but I didn't know she's from SHIELD." Tony started to get very suspicious about what was going on and started to make assumptions. "Why are you asking me this?"

"Was, a part of shield" Nick corrected. "When we lost track of her, almost 9 years ago shortly after you two coincided, it was because she had been making a lot of progress in uncovering one of HYDRA's most guarded and potentially dangerous projects. You know already HYDRA, your father made an excellent work helping keep the world safe from HYDRA's hands. Well, there was something Soulard must've been really scared of, something she was really anxious to protect. She knew things we didn't about said project and HYDRA must've known somehow, which made her runaway. She did it perfectly, changed her name, tried different identities, not even us could find her. We did get some sightings of her, some place different every once in a while in western Europe, she was playing hide and seek and had been winning until last week. We received a message from a burner phone with the words Winter Soldier and a file added to it, but when we tried to reach the file it had been deleted. We knew it'd been her and we tried to find her but she really did an amazing job at keeping her location a secret. It took us a couple days but eventhough she used a burner phone, thanks to it, we found where she was living. Right after, us two and a couple agents went to her place, somewhere in a small town in northern Italy. We knew time was limited, because if we could've found her, it was a matter of time until HYDRA could to, and whatever she was trying to tell us was worth risking whatever she had been running for all these years. When we made it to the apartment, it was too late for her. We found her laying murdered on the floor next to the man that killed her, an HYDRA agent, who also didn't make it. What you should know, Tony, is she left something for you."

Tony was confused and getting creeped out by the situation, what he tried to ignore by acting cocky and unbothered.

"That's a shame, really, but I still don't get why this involves me. I get we had something, but what do you mean she left something for me, it's not like we were in love or something, it was a night almost 9 years ago, an amazing night, but that's all. What could've she possibly leave for me? What, are you going to tell me she left me? A love letter? An 8 year old kid of mine?" He said hiding his nervousness behind his jokes.

He laughed but no one else did, in fact, they looked considerably more awkward after that last thing he said. The room went silent.

"She's almost 9, and her name is Sienna." Nick said lowly.

They knew because when they took some blood analysis to make sure the girl was okay, they also checked it was Gisele's biological daughter just in case. So when, the results seemed to have compatible ADN, not just with one, but with two familiar people they had analysed before, they found out both her biological parents.

"It can't be real, it's not possible." Tony thought. He had to see it with his own eyes to believe it. He knew he hadn't always been careful with his affairs but he never believed it would actually turn out like this, even less with that Soulard agent.

But if this was true, it changed everything. Being Iron Man was a thing, but being a father? He wasn't ready for that. His own father-son relationship hadn't been to be proud about, and he never expected to have to build his own. A million thought went through his head.

"I need to see her." He demanded.

So that's where they took him. About to enter the room where I was waiting to meet the man who would take my custody, he paused before stepping in. He was terrified, because he had no clue what could happen next, what would he do, and he always knew. After taking a deep breath and feeding from his ego, he stepped in.

I was watching the fish tank, pretending to be clueless, pretending not to know the depth of the matter. For the last few days everything felt empty, like the world stopped spinning. I'd lost everything and everyone. It was like my life never existed, like I never existed, and now I was just some ghost. Nothing felt real. I barely'd felt emotion, until now.

The door opened and I knew who were coming in, who I was about to meet. There I felt emotion, I was scared to death to meet my father. All my life thinking I didn't have one, that made me feel bad, but now I think it's even worse to have one. Because how am I supposed to act now, what if I don't like him? Or if he doesn't like me? I crossed eyes with him and suddenly everything was a little less scary, because I could see that he was even more terrified than I was.

When Tony saw that kid's eyes, there was no doubt left, it was his eyes. Him, that always had something to say, went speechless. She had short brunette curly hair and a pair of beautiful brown pearls for eyes like Tony's. She surely took that european essence from her mother, but still Tony's resemblance was presence all over her whole being. He noticed how the little girl was wearing her childish clothing under an obviously way too big jacket for her they must've given her.

Everyone left the room, leaving the two of us alone. He came closer to me, carefully as if he was walking on eggshells. I waited for him to say the first words, but he was as stunned as I was.

"Hey, I'm Tony" He introduced himself, without any idea of what else to say in this situation. He knew this was big for him, but he knew that it's a child he's talking to. A child who just lost his everyone and whose life had just changed completely at such a young age, it was a feeling he'd known well. So he ignored any uncomfortableness there was in his body and took the lead as the adult he was, as the father to be.

"I know." I said awkwardly, but grateful he started the conversation. "I'm Sienna."

"I know that too" Tony smiled trying to comfort her. "I'm deeply sorry for your mother, she was a great woman."

I looked down, appreciating his words but with no come back. Because every time I thought about her, i just shut down.

"I'm going to be honest with you, and it's something I don't usually do with people, but this has caught me by surprise, so I'm sorry if I don't do it the right way but I don't know how to handle this. But, I will try and we can figure it out. I know this is harder for you than it is for me. So I want to help you."He put his hand on my shoulder. Avoiding looking directly into my eyes, as he was unfamiliar to that closeness.

I gave him half a smile. I still didn't trust him, but it wasn't like I had any other option. When these people told me I had a father to come pick me up, I couldn't believe it. My mother had lied to me, I thought we never lied to each other, she was the one person I ever trusted. But ever since she'd been gone, it appears my whole life had been a lie, so who could I ever trust now? When they told me about my father, I didn't want to believe it, I didn't want them to be right, but when I saw this man... How he looked, how he talked... It was as familiar as the face I see everyday in the mirror.

"Do you want to get out of here? This place is depressing. Are you hungry? We could go eat something and get you some clothes." Tony offered. He didn't know how he should act, but kid's were always hungry right? That couldn't go wrong. And the girl surely needed some new clothes.

I nodded and stood up, so did he. We walked in silence out that room, with his hand behind my back, which felt surprisingly right.

He made me wait some time more, while he talked some things with those people, probably about me. I was really nervous, but nervous was a feeling, and I hadn't felt that much in the last days.

"You can go now Tony, but please this with patience. She's a really special girl, who's been through a lot. And she needs a father more than anything right now. This is going to be hard for you but we'll be helping and looking after her." Agent Hill said, before letting Tony go. "We both know what kind of man you are. She's your daughter, but if you screw up, we'll take care of her for you. Don't make it come to that, Tony."

He got offended by "what kind of man" he was, but deep down inside him he knew she was right. He didn't say anything back, his ego was strong in these situations, but the real situation here was a kid waiting for him outside that room, his daughter. So he grabbed his things and went for me.

"Do you like burgers, kid? We're gonna get some burgers." We left the building and got in a car that was waiting for us outside.