Sorceress Natasha, because fuck it. Series is being posted on AO3.

Natasha is relaxing in a bar a few blocks down Avengers Tower when she feels something odd. She frowns and looks around the crowded room. She can't actually tell what it is that puts her off and scanning the place, nothing seems out of the ordinary. She's about to just turn back and write it off but the feeling keeps nagging at her and so she checks one more time. Her gaze skips past a young man in the middle of the room and she stops. It takes her a second to decide to get up and see what it is about him that has gotten her attention. Her gut is never wrong. He looks normal enough with his beanie and casual clothes but she trusts her instincts.

"Hey."

He looks up at her with a surprised smile and the brownest eyes she's ever seen. Ordinary. It irks her for some reason. Like it's unnaturally so.

"Hi. Can I help you?"

The accent is striking and she sits down across from him, putting her drink down on the table. She shrugs in reply to his question.

"What's your name?" She asks instead.

"William. What's yours?"

"It's Natalie."

She watches him tilt his head to the side like he's trying to solve a puzzle. He takes a sip from his drink and she notes that it's Vodka. Probably the same as hers.

"You don't look like a Natalie."

Natasha raises her eyebrow at that but he doesn't continue. There's something about that statement that doesn't sit well with her. She finishes her own glass and leans forward to smile at him. Oh, there is definitely something wrong with him. She doesn't know what she's seeing but she thinks it's something and when she's close enough to touch him, she feels a familiar chill around her. The pieces click together instantly and she rests back in her chair, a mask of indifference replacing her smile.

"And you don't look like a William."

She sees the shift in his eyes but it's gone as quickly as it came. Instead, he smirks at her and it's so eerily the same as his, he might as well not even bother trying.

"This is most interesting, is it not?"

Finally, she can place the accent and while his voice isn't quite right, it's close enough. Natasha can't risk anything here. Not when there are so many innocent people around, but he doesn't have that same worry and she knows it.

"Come with me."

At least nobody is going to ask questions when they leave together like this. She trusts him to be intrigued enough to follow her out and isn't disappointed when he does.

They walk out and into the next deserted alley, away from the general population still crowding the streets at this hour.

"What are you doing here?"

Loki eventually drops his glamor and he stands before her in all his Asgardian glory. Like a king, she thinks before vanishing the thought away and replacing it with fallen prince.

"I came to test a theory."

"Explain." She grinds out.

She doesn't have time for this. He smiles like an excited kid at the end of Halloween, finally allowed to eat all his candy. She doesn't like it.

"You, my dear spider, are magic-sensitive. A rarity among mortals, I must say."

She frowns. What is he talking about?

"There are few mortals capable of using magic and even fewer are any good at it. But all of these can feel magic when it is used around them. You are a rarity amongst those that can sense it. My magic is very subtle. It takes extraordinary skill, or in your case sensitivity, to notice it. It took you a mere minute to feel it and filter me out as the source. And recognize me on top of that. I've done well in keeping you alive."

The last sentence is added as an afterthought but Natasha isn't paying it much attention. She's trying to figure out if he's kidding, toying with her. She doesn't think he is. She decided to roll with it. For now.

"I can still feel something off about you." She starts tentatively, "It's been there since the first time."

Loki takes one of her curls and twirls it around his finger. He doesn't reply for a minute, seemingly fascinated by her hair, and she waits it out. He'll probably lie to her anyway.

"The glamor Odin put on me as an infant. You sense it like you sensed the one inside the bar."

"It's permanent?" She asks, trying not to let her surprise show. She hasn't expected a genuine answer.

"Yes."

He sounds torn between relief and bitter hatred. She knows that feeling all too well. Natasha remembers what Thor told them about him. He's adopted. A Frostgiant. They're big and blue with red eyes. Monster, she adds for herself, that's what Loki thinks he is.

"What now? What's your grand plan?"

He looks at her and she's almost at a point where she feels uncomfortable. That's new. He releases her hair and for a moment, she thinks he'll smirk like he always does but it doesn't come.

"I want to teach you."

"Excuse me?"

"You could be a marvellous sorceress."

"I don't want to wield magic."

Loki looks a little hurt and for a second she's almost sorry but the feeling passes when he scowls at her.

"You would turn me down? I am one of the most powerful sorcerers in all the Nine Realms and you would refuse me?! Do you think I offer this to anyone-"

Before he continues his rant, she speaks up.

"And you don't think Thor would ask questions, or notice it? That it'd be like yours? That none of them would wonder how I suddenly do things I could never do before?"

"Thor would not notice."

"No, he would. He's smarter than you give him credit for."

Loki ignores her and his rant goes on. He's annoying when he does it. When he's a little calmer, he huffs and stares her down.

"Tell me then, do you believe in soulmates?"

"No".

His frown turns into the most curious expression then.

"In many realms it is believed that there exists a person that is uniquely attuned to you. That is what you refer to as a soulmate, is it not? Many never find that person for it is well possible they live in another realm. Not many travel between realms so their chances of finding that person are slim. We are that for each other. We were made to be together, Natasha. Why else do you think the sceptre accepted you as its wielder? Banner could not have done anything with it. Neither Thor or any of your friends. Only you."

"Bullshit."

His reasoning is terrible and she doesn't buy it. Perhaps the sceptre accepted her but she fails to see how that makes them soulmates.

"Perhaps to you."

Natasha is quietly observing him, trying to spot the lie. She doesn't believe him but she can't find a lie in his words either. Her best option is to entertain him.

"What's in it for you? If you were to teach me? What makes you so sure that it wouldn't backfire on you?"

"Oh, but isn't not knowing half the fun? I could make you a powerful sorceress, perhaps even an ally. Or maybe I'll just turn you into my pet. You would not be able to best me, no matter how talented you may turn out to be. But you could become stronger than any of your friends. Anyone on this pathetic realm."

She doesn't care to be but she doesn't say it because he's already unstable and he'd snap. She can't risk it.

"Become my pupil, Natasha. One way or another, you are mine."

Just like he is hers, if she believes what he's told her and cares to turn it around. He disappears before she has the time to reply in any way. The whole Loki situation has just turned a lot more downhill than it already has been. She should tell Thor that his little brother is around.

By the time she reaches the tower however, she has changed her mind. Loki is hers to deal with, especially if he's not interested in killing her.

When she spars with Steve and Clint the next days, she's unfocused. She's hoped to clear her head but Loki's words occupy it and she can't shake them. The boys are worried about her. It's not like her to be so out of it. Least of all when training. They don't much believe her reassurances but she doesn't go into any details and they eventually stop prying. Natasha hates feeling uncertain. She actually does believe Loki was being genuine for once and it's that that puts her off. She can't just ignore an attempt at honesty. Not when it comes from him. Neither can she ignore the pull she feels whenever he's close. It's like she's drawn to him and it irritates her. She doesn't even like Loki.

She feels his presence in her room not a week later. It's a bold move to show up at Avengers Tower when everyone is in but he's still hidden from plain sight and she doubts JARVIS is able to pick up he's there. He might not be visible but Natasha knows exactly where he is. She can just imagine the smug little smile on his face. She'd be wrong though. Loki is just observing her silently, contemplating.

Natasha leaves for the bathroom and he follows her. He knows it's an invitation to. JARVIS won't listen in there. She closes the door when she's sure he's in and then turns around in time to see him drop his spell and appear before her.

"Have you reconsidered my offer?"

"Have you?"

He steps closer to her and she feels oddly overwhelmed by his presence. She wonders if it's his magic making her feel like that and she takes a step back, colliding with the shut door behind her.

"I felt it from the first time you were close, flying us to your fortress in the sky. Magic is a powerful thing. You are a fool ignoring it."

"Why do you want to teach me so badly? You don't believe in soulmates any more than I do."

"Perhaps." He pauses, considering his next words carefully. He needs to sway her but he can't be too honest or misleading. "But I know something extraordinary when I see it. And your sensitivity is especially tuned to me. There is no one else like you. Anywhere. There lies great potential in you. I'm offering my help in unlocking it."

She's still beyond sceptical, of both him and his offer. It doesn't seem right.

"Imagine all the things you could do. All the benefits to your work. I could teach you anything you wish. You could balance your ledger."

He's mocking her but then he's not and she curses him because if he's serious – and if she just thinks it over for even a moment – then it doesn't sound so terrible. She could understand the way he fights better if he ever steps out of line again. She hates him for bringing up the one thing that will make her consider almost anything. In a moment of weakness, she agrees.

"I hate you." She adds just for good measure.

"We will start tomorrow."

Just like that he's gone again. What has she done?