I'm not going to end up finishing this fic, I've lost the motivation for it and all but left the fic fandom for this (I still love all the cannon content ofc, but I no longer read or write fic for this fandom).
That being said, rather than leave the story forever, you all deserve to know where it was going and how it ends.
I will warn you, however, that like most things in life it is neither an easy story, nor a happy one.
Max stays away from Steve and Bucky for a while, for safety reasons. While she's away she becomes more invested in tech and learning, trying to make herself as valuable and as versatile as possible for when she will eventually fight as a hero. Max receives visits from various Avengers who teach her new skills and come to know her and care for her.
Max receives a suit, designed for a hero, from Natasha one day and it is the best day of her life. She finally feels that she is living up to what she was training to be. A hero.
Shortly thereafter Max begins going on small missions and doing vigilante type work, similar to Spider-Man, and grows a bit of a following and fans. She's doing well for herself, she's learned well, and she's doing good work which is all she's ever wanted. She becomes a bit of America's sweetheart, and begins appearing in magazine and newspaper articles, and requests for interviews keep piling up; Max wants to take them but Steve is against it. He wants Max's identity to remain secret so one day she can live like a normal child/teenager. When she's an adult she can make the decision to keep fighting or to obtain civilian status.
Eventually Max is cleared to go on a small mission with Steve, nothing too dangerous, just an old abandoned facility in the middle of buck tooth nowhere with nothing around for miles. It's believed to have been used for dark purposes, but there's not enough info on it. It's played up to look like only Max and Steve, but naturally Bucky joins although he is not officially on the mission. They make it to the facility, a large compound of a few buildings surrounded by miles and miles of woods, and they spilt up, Steve going one way and Max and Bucky another. The duo walk through the halls scoping out the layout. They find dozens of labs, rooms with reinforced doors, arenas, and cells. Whatever this place was, it was incredibly insidious. Bucky is disturbed by what he sees, and Max... Is practically silent, visibly uncomfortable.
Steve finds his way to the main administrative center, the computers won't boot up, no power, but he finds filing cabinet upon filing cabinet of paper records. Steve is shocked by what he finds.
The structure is weak already, but the team quickly finds themselves in danger when the place begins to fall apart at the seams, and they don't believe it was normal wear and tear, but there's no way to know exactly who or what was behind the destruction as no one came after them.
They build camp a short distance away, possibly to go back the next day and search through the rubble for anything else. Max has remained quiet, seemingly haunted by what she saw. After a long period of tension, Steve finally asks her what she knows about the place.
Max clearly doesn't want to tell him, but she eventually caves and tells him what she had told Bucky earlier; that she was made to be a replacement, and that that facility had been where she was raised. Steve angrily shouts at her, demanding the truth, before tossing some files he had stolen in her direction.
They are Max's files, along with two others, other children in the program. They are marked with Hydra symbols and display a long record of bloodshed at her hands. Max flips through the files, Bucky reading over her shoulder, reading with horror at the records kept. They had been trying to recreate the serum from birth... But not for good. Max was never supposed to follow in Captain America's footsteps... She was supposed to follow the Winter Soldier's.
And she had been their strongest. Her, along with the next number in her sequence, her twin brother, in a sense, had crushed and destroyed all others put in their path. Their biggest fault was their volatile interactions with each other.
Max's file had been stamped "unrecovered", all others were stamped "eliminated".
After Max had escaped, the program was no longer being funded by the Hydra organization, and the project was retired. With nowhere to put these extremely violent and hostile soldiers in the making, they were all killed.
Max is understandably distraught, and she throws the files into their campfire before rushing off deeper into the woods. Steve makes to follow her, concerned she is fleeing because he discovered her true secret, but Bucky stops him and sets him straight explaining how she was never meant to be Steve's replacement as she believed, but had just now learned what she really was, and had come face to face with the horrors she carried out. Bucky goes to find Max, locating her sitting numbly under a tree a distance off.
There she explains how, she didn't remember any of that before, but as she thinks more about it she can remember bits and pieces.
She had been ruthless back then. Hungry for blood any way she could have it. They encouraged extremely volatile and sadistic behavior, believed it would strengthen the desire to kill when ordered, would systematically suppress any desire to be merciful if the pleasure derived from fighting, beating, and killing won out.
The subjects would be locked in the cells, only let out for sparring and testing. She spent most of her time in the labs, fighting, or sitting idly in her cell. Rare times, she would be put in a small room with one of the weaker subjects, a final effort for them to prove they were worth something, or die trying.
After a life made up of this, day in and day out, the leading scientist on her case began feed her information and truths about the outside world. It didn't stop her desire to hurt or kill, but it did make her compliant to his plan to escape with her.
After she and this scientist escaped, they were constantly on the move running from those who tried to capture them to return Max, or as she was then known, subject 245, Max became less and less indoctrinated to her wats of bloodlust, being fed stories and pumped full of drugs the scientist would make, reversing some chemical nature in her brain. The stories she was told were a way to change her for good, and coupled with the powerful drugs Max was convinced of her program being that to replace the super soldier and convinced that the facility had been a training camp, and that that scientist had been as close to her father as she would ever get.
Eventually their past caught up to them, in the middle of the night Max woke to gunshots and fire, and in a last ditch effort to save herself and get away, she called on the ruthlessness inside her and did what she had to do to get away. She killed them and ran. After that, she was on her own, traveling the rest of the way through the country until she found where Steve and the rest of the Avengers were in New York and set out on a quest to find him.
After this mission the relationship changes, although Steve finds a way to not be mad at Max, understanding that's not who she is anymore and that her past does not define her. Max still performs hero duties and is beloved by the people, but she appears less and no longer delights in the attention.
Bucky goes back to trying to hide from heroes and villainy, trying to live as close to normal life as possible.
With the introduction of the issues stemming revolving Civil War, Max tries not to take a side being that she's such a public figure anymore. Although at every encounter she is faced with people calling for her to make a choice between one side or the other. She attempts to be as diplomatic as possible however she can be no one seems to want go listen.
Finally, Max sets up a public and live interview that will be broadcast far and wide to tackle these issues. She removes her mask and speaks candidly and openly about her beliefs and uses her own story,to illustrate the fact that most heroes were not born with a choice to choose their powers or how destructive, and howitzer is inconceivable to restrict the use of those powers to specific instances where a limited number of people can decide how they are used. It's a matter of rights, and no matter how you slice it there is no clean answer.
Although this creates sympathy for the Avengers and heroes in general it puts Max in extreme danger. The files were wrong, Max was not the only surviving member of the program. Her counterpart is alive as well, and he is just as ruthless and bloodthirsty as when they fought head to head long ago. Subject 246 is the only kept product of the project that was deemed to be a failure, and he was just sent after Max to kill her.
A few days later, Max is doing her regular hero activities and being a public figure when she is attacked. She realizes quickly what has happened and knows what danger she is in. Although she knows nothing but death will stop him, she fights more defensively than offensively, not willing to lose herself to that bloodlust again.
Max is just successful enough to survive this encounter, but 246 escapes before she can truly bring him down. Max is on guard for the next encounter, but she knows that she will never end this unless she stoops to his level. They may have fought for dominance in the past, but Max knows this time she has to be victorious once and for all.
She contacts Bucky and tells him about the situation, he does everything he can to be near her in case of an emergency. Although he knows Max needs to finish this for herself, Bucky still blames himself in some regard for being the root cause of her suffering and this mess.
It is weeks later, Max is in public with Steve when she is next attacked.
She never saw it coming.
The bullet entered her left upper torso.
She was sixteen.
Because Max was such a public figure there is a push for a large funeral to be held for her, although there is a smaller funeral held so those close to her can openly grieve without worry for what the public and media will think. In all of the images and coverage of the tragedy show Max depicted as a young girl. Steve can't get the image of her dying in his arms out of his head, remembering how small and scared she looked in that moment despite how she tried to cover it up and remain calm.
Bucky swears he is going to find the bastard that shot her, stating that simply killing him would be merciful. He knows he won't be prepared for how young the boy will be, but he keeps telling himself it's necessary.
After a short period, a memorial is erected for Max and the good heroic work she did, remembering her not for what she was meant to be but for who she became. She is depicted not as a hero, at Steve's insistence, but as a young girl who still had her whole life ahead of her. She smiles warmly, hand outstretched, beckoning those who encounter her to join her.