Summary: Tony Stark's father was never around and his mother never paid attention. But he was never alone. He had his nanny. His mysterious nanny that changed the Marvel universe forever...

Warnings: Slight angst, swearing

Pairings: None

Disclaimer: I own nothing.

Howard had met her in Japan on a business trip. During the meeting he was attending, she had come out of nowhere and got in front of him as a gunshots rang out and knocked them both down. In his haze he had looked up and saw that she had gotten off of him and had three bullet holes in her, yet she was standing like it was nothing. Howard had watched in shock as the wounds knit themselves back together and the girl (she looked barely twenty) looked like it was a common occurrence.

She accompanied him to the hospital and he asked her if she would like to be a nanny-slash-bodyguard for his six month old son. She was silent for several moments before giving a curt nod. On the flight back to the states she said only a few sentences in a monotone voice.

"Call me Black Thorn. I don't trust you enough to tell you my full name."

After several months Howard noticed that Black Thorn always wore the same thing and always carried the same weapon with her. A knee length black dress with what can only be described as having 'tank top sleeves', buckled black pumps with thick heels, fingerless black leather gloves and a silver locket hidden underneath her dress. She also wore what can only be described at a black half mask that covered her mouth and nose and only showed her dark brown eyes that always seemed to be calculating something. On top of her half mask she also wore a black scarf around her neck. Black Thorn also had chin length pitch black hair that was choppily cut and she had some of her bangs covering her forehead and face.

Her primary weapon was a katana strapped to her back in (you guessed it) a black sheath. After an attempted kidnapping, Howard found out that she had a black knife attached to each of her thighs under her dresses skirt.

Anthony was four when he build his first circuit board. He was in the living room making it with Thorn (as he called her) reading a book on the couch while keeping an eye on him at the same time. When he completed the board he grinned proudly at her and she gave a small nod at him. Anthony looked up as his dad walked into the room, muttering about a search in the arctic. Tony held out the board with a proud look and Howard ruffled his hair without a second glance before walking out the door, still muttering.

Anthony seemed to wilt right then and there as his father seemed to just disregard him. Thorn stood up and before Anthony knew it, she had kneeled down and wrapped her arms around the young boy. Anthony buried his head into her chest and silently cried, clutching the circuit board to his chest. Thorn glared at the door Howard had exited and shook her head lightly.

She wondered if Howard even knew that his son preferred to be called Tony and not Anthony.

When Tony was six and built his first engine, Howard acted similarly to the Circuit Incident (as Tony called it) and Thorn was left hugging and comforting the boy once again.

On that day she told Tony that her first name was Saya and divulged a few key pieces of her past.

It was also the first day Tony called her 'Big Sister'.

When Tony graduated at seventeen, Thorn was the only one who came and watched. She didn't trust Obadiah and told him it wasn't necessary for him to come (in her opinion, he was a little to happy that he didn't have to come).

The next day, Howard and Maria died in a car accident.

When Tony went missing, Thorn contacted a few of her less-than-honorable friends and they managed to give her coordinates and she gave an anonymous tip to Rhodes to Tony's location.

She had never been more proud when her 'little brother' announced that Stark Industries would no longer be manufacturing weapons.

At Obadiah's betrayal, she barely kept her usual monotone expression on. Plus, while protecting Pepper, she was very grateful for her healing factor.

Tony had gotten used to Thorn's monotone personality through the years (he was probably the only one who had seen her show emotion).

He was also the only one who had seen her without her half mask on. (She was quite pretty). When he came back from being kidnapped, she had told him almost everything.

She told him of how she was born in 1829 (age 183) and had stopped aging at around 18-20 years, she told him of how she discovered that her blood was acidic/poisonous, and she told him of when she had met Captain America in passing. ("He was polite, kind, and not afraid to get into a fight and protect those he cared for. He reminds me of you in a way.").

Tony's opinion of Steve Rogers had gone up after that and when he discovered that Captain America was alive he took upon himself to show him how much the world had changed. When Steve had met Thorn again he was shocked and the three of them bonded (with Natasha) over how fucked up their lives were sometimes.

When New York happened, so many people were surprised when a young girl wielding a katana and two knives began killing aliens left and right.

(Thorn nearly killed Tony when he can down from the portal)

Everyone got to talk to her properly after the battle over shwarma (they liked her despite her monotone personality).

When it was discovered that Bucky was alive, Thorn found him first after DC and managed to talk to her friend Charles Xavier about helping him. Steve had never been more grateful. When people started calling him a murderer, she contacted Matt Murdock and with his and the rest of the Avengers help got him cleared of all charges (Though Tony was upset when he discovered about what really happened to his parents, but Thorn brought him around).

A while later, there was a huge battle with Ultron and in the end Thorn managed to save Pietro from staying dead (it turned out that even though her blood was poisonous, it the person was already dead it had healing properties).

After that it was discovered that Loki had been brainwashed and after some help from Xavier, they managed to stop a mad titan by the name Thanos (with a group called the Guardians of the Galaxy) from doing any more damage.

So many years later, Thorn was training the Avengers kids (along with her own) to be superheroes. Then she taught the Avengers grandkids as well.

Content with everything that had happened to her in her 279 years of life, she managed to get into contact with Death herself,

and on August 4th, in the year 2109,

Thorn died on her birthday at 280 years old,

reunited with the original Avengers and with her dearest little brother.

Even after so many years, she had never forgotten his smiling face when she praised his inventions, or when she hugged him when his parents didn't.

Epilogue

In Heaven, the first thing she did after seeing the Avengers, she walked up to Howard Stark, and punched him in the face.

Then, for the first time since she lost her father, she cried. Only this time, it was happy tears.