Nezuko awoke to the sound of roaring coming from the living room. When she went to investigate, she found a holographic display surrounding her uncle in the living room. Pepper stood to the side looking confused, and a balding man stood by the elevator. "I have no idea what's going on, but I want in," stated Nezuko. "And who are you?"

"Agent Phil Coulson, at your service," the newly identified Agent Coulson says. "And what makes you think you can contribute anything, or really want to?"

"I see Thor, the Hulk, and Captain America. I'm pretty sure this is something I want to be in." Nezuko continues, "And as what I can do, I am good with a sword; I can set my blood on fire, which heals humans and hurts things that are non-humans in the surrounding area; and I am like a cockroach-I will survive getting my head cut off."

"Fair enough," says agent Coulson. "I can see how you could be an asset."

"No way, José," Tony counters. " You're only 13 and your mother would kill me if you got involved with this."

"But this will involve me either way. The only difference is that I do something about it, or I don't," Nezuko cut in. Her eyes suddenly start glowing with a demonic light. In a deceptively soft and sweet voice, she says; "Face it, there's nothing you can do."

"She does have a point, you know. There's nothing you can do." Says Agent Coulson. "So Ava, what do you need?"

"I'll need a katana and night vision lenses," Nezuko says. "My code name will be Slayer, and if the public asks we tell them my name is Nezuko Kamado."

"Do you have a costume?" Phil asked, wondering why she didn't request one.

"Yep! Let me go get it," Nezuko replied. She ran off, returning dressed in a modified demon slayer uniform (all she did is turn the pants into a pleated skirt, reminiscent of her former sister-in-law's uniform) and a haori with a hemp pattern identical to that of her favorite kimono in her past life. To finish it off, she had a Japanese cat half mask that had pink camellias in one ear; gold paint detailing; pink tassels; and sakura flowers painted on. Nezuko was very proud of her outfit, as she made most of it herself; with the exception of the mask. She had just decorated. "So where are we going?"

The reply? "Stuttgart, Germany."

A/n

The mask looks like this: https/pin/751397519060619683/