Maybe it was someone from her past in the Red Room. There could have been a forced relationship during her training days, and the consequences are now the baby. This would add a lot of drama and a darker tone to the fanfiction as she has to deal with this part of her traumatic past while raising the child.
One possible plot could be that Black Widow discovers she has a baby unexpectedly. Maybe it was a result of some sort of experiment she was involved in long ago without her knowledge. She then has to figure out how to protect the baby from various threats, like the enemies she has made over the years in her dangerous lifestyle.
Hawkeye and Black Widow are the central figures. Hawkeye with his sharpshooting skills and down - to - earth personality, and Black Widow with her spy - like skills and complex past. The baby is the focus of their attention and the story. And then there are characters like Iron Man who might be involved in providing resources or technological support to keep the baby safe. Thor could also be a part of the story, perhaps using his godly powers to shield the baby from threats.
A Black Widow and Hulk baby in fanfiction could be really interesting. Since the Hulk has superhuman strength and the Black Widow is highly skilled in combat and espionage, the baby could be a force to be reckoned with. It might grow up having the Hulk's green skin and incredible strength, but also the Black Widow's intelligence and ability to deceive opponents. It could use its strength for good, like protecting the weak, but also use its mother's skills to outwit villains. For example, it could break through walls to reach a hostage and then use stealth to surprise the kidnappers.
Another aspect could be the relationship between Black Widow and Hawkeye as parents. Since they both have had difficult pasts, they could be either overprotective or determined to give the baby a normal life. They might teach the baby different values based on their own experiences, like Black Widow teaching self - reliance and Hawkeye teaching patience and precision.
Perhaps a storyline where the baby is raised in secrecy. Hawkeye and Black Widow are constantly on the run to keep the baby safe from their enemies. The baby grows up learning survival skills from them. And as the baby gets older, it starts to show signs of wanting to be part of the superhero world, despite the risks. It could also involve the baby having to face some internal conflict, being half - Hawkeye and half - Black Widow in terms of abilities and personality.
The other Avengers like Captain America, Iron Man, and Hawkeye are likely to be involved. They are her comrades, so they would be there to support her during her concussion recovery.
One way to develop the story is to focus on the baby's upbringing. It could be raised by the Avengers, who have to teach it to control its powers. Another aspect could be its relationship with other superheroes. For example, it might look up to Iron Man as a mentor in using technology to enhance its abilities. Or it could have a special bond with Captain America, learning about honor and leadership. The story could also explore how the baby discovers its true potential and how it uses its powers for the greater good.
One idea could be the unique powers or abilities the baby might inherit. Maybe the baby has Captain America's super strength and Black Widow's agility and combat skills. Another could be how the Avengers community reacts to this new addition. Some might be overjoyed and protective, while others could be worried about potential threats.
It shows a more domestic side of them. Usually, we see them as badass Avengers, but in the fanfiction with a baby, we can see their nurturing and caring sides. For example, Hawkeye might be the one to wake up in the middle of the night to soothe the baby, using his calm demeanor.