Author's Note: The idea for this story came about four years ago when I first got into SnK. I never ended up writing it and sometime during the Uprising arc, I left the fandom due to other things drawing my interests. I just got back into SnK earlier this year and so I finally decided to write something for a much beloved series and probably one of my favorite pairings, Mikaani. The original idea is really just a smutfic, but now it has evolved into an overly long smut turned romance fic. Fair warning to those here for Mikaani, this fic also has Ereani and there is a lot of Ereani to go through before the end. Also general warning for infidelity/cheating.

Annie has known Eren three months before it comes out that he has an adopted sister. An older sister, but only by a month. He makes sure to stress that part. He mentions it briefly in conversation, and the mention is almost passing. She doesn't mind, attributing it to a disinterest in talking about family, which she shares. But at this point of their relationship, where it feels like it could go further, the topic hangs overhead like a formality that needs to be overcome. So he talks. And she talks. Two weeks after that talk, he asks her out on a real date. Not coincidental dinners, or after hours drinks. But a relationship starting date. And she accepts.

She meets Mikasa for the first time a month into the relationship. It's incredibly informal, Mikasa arriving as a post-date ride home after walking home plans are interrupted by sudden heavy rains. From his face, it's obvious this isn't how he plans to introduce them, if he plans to introduce them at all. But with no umbrella and no desire to brave through what must be stuffy public transports or musty taxis, he has no choice but to call for a free ride in what he knows is an impeccably clean car. And it is. Shiny jet black exterior with a spotless dust-free interior. That itself tells her more about Mikasa than Eren ever has.

Mikasa herself is civil, if unsociable. She greets Annie when she enters the car, pretends she doesn't exist for the rest of the ride as she talks to Eren, and then bids her goodbye when Annie gets off. Not that Annie minds. If she gleams anything from that meeting and observing how she interacts with Eren, it's that she and Mikasa are more similar than she imagines. That and the fact that Mikasa now knows the apartment building she lives in. She isn't quite sure why she finds that particularity unsettling. But as she takes the stairs up to her unit, thinking about her schedule tomorrow, she puts it out of her mind.

The second time she meets Mikasa is mere days later, when Eren, clearly still dissatisfied with how the first meeting happened, invites her over for a dinner thing to properly introduce her to Mikasa and his childhood best friend, Armin. To make things fair and less awkward, or possibly more, she brings along her own childhood friends, Reiner and Bertholdt. It goes better than she expects, with Reiner being a great conversationalist driving all the conversations, while Armin expertly follows along on their side. It makes up for the quieter Bertholdt and Mikasa, and Annie finds herself enjoying the night quite a bit.

She ends up learning several things from the dinner. Firstly, that Armin and Mikasa are precious people to Eren. He doesn't actually say so, but she sees it in the way he talks to them, the way they act and react to each other, the air of comfort and compatibility surrounding them. It's something she sees in herself, Reiner, and Betholdt, although in a different sense. Then she puzzles over why, when they are so close, it is only now that Eren brings her to meet them? Why hasn't she heard about them earlier? It's almost as though Eren is keeping this part of his life separate from her. And then she realizes that that's exactly it. Eren knows she's a private person, so he's making sure that a relationship with him is exactly that. A relationship with him, not including his family and friends. She finds herself immensely appreciative of that and when everyone else leaves after the dinner thing, she sticks around to show him that he too is in a relationship with her and her alone.

The second thing she learns is that Armin is someone that she can get along with, surprisingly. There is absolutely nothing he has in common with her, but yet she finds herself at ease with him, and not minding his companionship. It's the kind of ease that lends itself well with get together lunches, or needing someone to kill time with. And it's exactly on one of those get together lunches that she gets the answers for the third thing she learns that night. A query involving Mikasa. Seeing her directly and not from the backseat of a car, what stands out isn't her exotic half-Asian looks, but the build of her body. Dressed in lighter, more casual clothes compared to the thick jacket she had before, and without the scarf at least during the dinner portion of the night, Annie notices it clear as day. And when she sees the way Mikasa moves, she knows it with a certainty afforded by experience.

That's a fighter's body. Just like her own. And she wonders, seriously wonders, why Eren hasn't mentioned this before. Surely he knows that she would find that fact interesting, being a fighter herself. Fighting is pretty much the only thing she can say she's passionate about. It's a passion she shares with him. After all, she meets him in a boxing ring where she kicks his formless feet from underneath him and slams his body so hard into the ground he probably sees stars. They bond over fighting. One of their favorite date activities is to attend local matches. And they talk about it quite often too. Fighters. Techniques. So it boggles her why Mikasa is missing from the equation. There's not even a passing mention.

She decides to ask, one time. "So your sister, Mikasa, what does she do?"

She asks because her fighter's body comes with the job description as a fight instructor. A well maintained body like Mikasa's must come from something similar.

"Mikasa?" he looks up, surprised. "Like her job? She's a translator. Got a PhD in three or four languages, not too sure, so she does all sorts of translation. Textbooks, fiction, research papers, poetry, websites, you name it. On the side she does some private tutoring too for college level students."

How terribly mundane, is her first thought. How terribly sedentary too. Not exactly jobs that should realistically lead to a great physical form. As for her third thought—

"PhD? Three or four?"

He flashes a tight smile. "She's exceedingly talented. Could have done anything she wants to."

"Oh? What else is she exceedingly good at?"

"Everything."

Despite the praise, his smile doesn't reach his eyes and his voice goes soft. She promptly skirts the topic. "I have a feeling she doesn't like me."

She senses it, during the dinner. Mikasa is subtle about it, very expertly subtle that Reiner and Bertholdt don't notice, but she's always been good at picking up these things. So she's quite certain she isn't wrong about the undercurrent of animosity beneath Mikasa's courteous facade.

"What? No way. They like you just fine."

He follows up by pulling her across a street they don't need to cross and changing the subject. That, coupled with an unconvincing look of disbelief and the random lumping of Mikasa together with Armin clues her in to the fact that for some reason, this is a sore subject. She decides not to pry. At least not from him. Armin, however, opens up quite easily on their get together lunch. Of course, under the condition that she keeps it to herself.

"Ah, Mikasa? Well, she used to like Eren, back when they were younger," Armin tells her while leaning back on the cafe chair sipping his fruit infused tea. "But even though they're not related, Eren thinks of her more like family so it didn't work out. She's over it, but I guess she does feel a bit jealous, perhaps? The is the first serious relationship Eren's been in, after all."

Annie similarly sips her coffee, black with no sugar, as she considers Armin's words. Jealousy checks out. It certainly explains Mikasa's behavior towards her, but not Eren's reaction towards the topic of Mikasa.

"Don't worry about it, Annie. I'm sure that if you felt any animosity, it's unintended. Mikasa just needs to sort out her own feelings. I can say for certain that she doesn't like Eren in that way anymore."

Not that she cares about that. Eren made his choice. Still, it is reassuring to know there won't be issues on that front. However, that's not the burning question on her mind. Placing her coffee down on the table, she asks. "I have another question about Mikasa."

What Armin tells her has her side-eyeing Eren for a while. Because yes, Mikasa is a fighter. And yes, she is exceedingly good at it. And yes, that's precisely why Eren hates to bring it up. Because she is better than him. Even Armin can only smile helplessly at her surprise, as though sharing her opinion on how strange that is. After all, the first thing Eren says after she floors him is to express awe at her technique. And then when she offers to teach him, he accepts with nothing but humility and eagerness. It's hard to imagine that same person now feeling inferior, and being bothered by it. Unfortunately, he is oblivious to her side-eyeing, and as condition for Armin's openness, she doesn't bring it up.

Maybe if she doesn't see Mikasa again, that would be the end of it. She's curious, she wonders, but with an inability to ask, without anything to feed the flames of her curiosity, it's only natural that it dies. But the formal introductions seems to have catalyzed something else in her relationship with Eren. Where before he keeps her separate from the other part of his life, now there is a clear overlap, if a small one. She goes over to his place more often and like clockwork, Mikasa is there too, every Sunday evening. And she stares at her like she's the one intruding, and maybe she is, but that doesn't mean she appreciates the snark.

"Ah, Annie. We always have dinner together every Sunday. It's a tradition impressed upon us by Aunt Carla, Eren's mom. You're welcome to join us, if you want."

It instantly raises her hackles how Mikasa's voice drips with pretend courtesy. Eren calls out his agreement from where he's seated on the couch, but she doesn't answer him. Not immediately, because Mikasa is challenging her. She is challenging her to invade into their family tradition, banking on the assumption that she wouldn't. And she really wouldn't. Not normally. But here, now, she finds herself not wanting to back down. So she makes it a point to show up every Sunday evening and even though she's not one for displays of affection in the presence of others, she also makes it a point to kiss Eren in Mikasa's plain view. It's satisfying at first, the startled look, the narrowed eyes, but after the second time Mikasa stops paying attention or turns away and then Annie begins to feel childish. But by then Eren seems to have been conditioned to expect a kiss, so she doesn't stop. It won't help the jealousy, but that's not her problem. She's no longer doing it out of spite. She just wants to kiss Eren. Thankfully, Armin shows up sometimes so Annie doesn't feel like a complete intruder.

Still, petty taunting aside, and despite wanting to get along with Eren's sister like she does his best friend, she can't help but feel a more fundamental dislike for Mikasa. It's a feeling she's certain Mikasa shares about her. Even so, her opinion of Mikasa has no bearing on her curiosity about her, and the weekly meetings are exactly the fuel it needs to keep burning. And burn it does, finally spilling over when passing by Mikasa through the narrow kitchen doorway, she sees the flex of her shoulder blades and the muscles of her neck from her wide collared sweatshirt. A lucky chance, considering Mikasa always wears tops with long sleeves, almost like she wants to hide her form.

She takes the chance. "You're well built."

Mikasa looks up from her plate and gazes at her from across the table. Funnily enough, Eren's fork stops moving too. "I work out."

"Yeah," Eren chimes in, eager, urgent. "You know, with that sedentary lifestyle of hers. She needs it to keep healthy and fit."

Annie ignores Eren, keeping her attention directed at Mikasa. "Oh? What kind of work outs do you do?"

Eren cuts in again. "The usual. Cardio. Weights. Right, Mikasa?"

"Yeah."

He makes a noisy mess of slicing his undoubtedly tender chicken breast, and then changes the subject. It bristles her, how he snubs Mikasa. It bristles her even more that Mikasa is unfazed, simply agreeing with him like he's done this a thousand times. And it's incredibly off putting to see his inferiority in action. If not for the fact that it will expose Armin as her mole, she would have called him out for it. Because that is not acceptable. But Mikasa goes along with his conversation change easily and when Eren pulls her back in she finds herself simply swept along.

That night when she pushes Eren down onto his bed and he yields to her willingly, a smile on his face and lust blazing in his eyes as she straddles him, she doesn't know what to make of it. She bites his ear.

"I'm always kicking your ass," she breathes. "Does it bother you?"

"No way," he counters, hands finding her waist. "You're amazing. I love how strong you are."

She really doesn't know what to make of it. So then she wonders if it instead comes down to a matter of levels. Eren can accept and admire her strength because it is only of a certain level, but he can't accept or admire Mikasa's because her level is so much higher. He did say that she is exceedingly good at everything, and Armin did concur to that. Maybe she shouldn't have gone down that rabbit hole of thought, because she finds herself, the next day, attacking the punching bag with such ferocity that everyone else in the gym gives her a wider breadth than usual.

She knows she's exceptional. There hasn't been anyone on par with her for the longest time because she has surpassed them all. She's even been scouted to fight professionally or to coach if she will not fight but she only declines because she doesn't want that kind of attention and responsibility. Eren, getting better every day, is still leagues below her level with not a single victory against her. Does that then imply that Mikasa's level is leagues above hers? She realizes too late that she really shouldn't have pursued this train of thought when that inevitable feeling creeps up on her and takes hold. The feeling of needing to know for herself.

It's not a matter of competitiveness. It's not a matter of win or lose. She simply needs to know how good is exceedingly good. And how does exceedingly good fare against exceptional. But she's not supposed to know about Mikasa and seeing as the only time she ever interacts with Mikasa is when Eren is also present, there's no chance to discreetly ask either. So even though it's not Mikasa's fault, she does admit the inability to sate her curiosity leads her to be intentionally provocative. One time she tries to accidentally bump into Mikasa, if only to get a feel for Mikasa's body underneath the concealing clothes. But if backfires spectacularly when Mikasa's reflexes has her swerving out of the way at the very last moment, leaving Annie to bump into air. Mikasa gives her a look like she knows that shouldn't have happened, that Annie's balance is better than that, and all Annie wants to do is challenge her right there.

She doesn't know what exactly it is about Mikasa. Someone as passionless as her, with such empty eyes, who doesn't even have enough pride in her skills that she'd hide it at someone else's say so, surely someone like that doesn't deserve her interest? Eren may be formless and lacks discipline, but in his eyes burns an uncontrollable passion. Like he's bigger than his own body. That's what's attractive about him. Compared to him, Mikasa just pisses her off. She can't place a finger on why. Mikasa just does.

But despite all her rationalizations about why Mikasa isn't worth her attention, it does nothing to ease the growing desire to fight her. One that gets worse when no one in the gym gives her any challenge at all. When the situation continues for too many days to the point that even the oblivious Eren notices something off with her, she finally decides to seek external help. The only person in recent memory that has given her a hard time. And he had probably been going easy on her too. He's a friend of her father, from when her father was still able to fight. But it has been some years since they last met, so perhaps she'll find the years has gotten to him. Then if not him, he might have a protege she can have a bout against. She wonders about that though, considering his dojo is not open to the public and his fighting techniques only passed down to members of his clan. As she understands it, the clan has become so scattered that there aren't many of them left. But there's only one way to find out.

It takes a train and a bus to get to the sleepy town on the outskirts of the city where his dojo is located. Not wanting to interrupt, she waits outside until the lights go off and sure enough, he emerges from within.

"Oh, who's that?" he squints, and then brightens with a laugh. "If it isn't Leonhardt's little rascal!"

She walks up to him and pays him respect as she would any master of their craft, with a slight bow. "Kenny. It's been a while."

He places a hand on her shoulder. "Indeed! Visit any later and you might only find news of my passing."

"It's not your time yet."

"Heh, not today anyway. Care to have a drink with this old man?"

She'd rather not, but it's as good as any opportunity to bring it up. "Sure."

He laughs again. "My lucky day. Having drinks with two beautiful ladies."

Two? Then Annie hears the metal gate of the dojo shutting behind Kenny, and an incredibly familiar voice rings out.

"I'm not drinking, Kenny. I told you I drove here."

"Don't be such a party poop—"

"Mikasa?"

Kenny cast glances between them both, and breaks into a large grin. "Two beautiful ladies who know each other. Even better."

Annie watches as Mikasa approaches them and then looks up at Kenny. "You opened up your dojo?"

The face Kenny pulls is an instant answer. "What? Why would I do that?"

Her gaze drops back to Mikasa. "But you're...?"

"Hm? Mikasa?" Kenny turns to her and wraps an arm around her shoulder. "She's one of us. An Ackerman."

Mikasa drives her home after drinks. True to her word, she doesn't drink a single drop. Annie never does bring up the reason she's here, but then again, Mikasa's appearance changes everything. She looks at Mikasa from the front passenger seat, wondering why she'd just assumed that Mikasa is a Yeager like Eren. She's adopted, and thinking back, Eren never mentions her surname during introductions. It's just assumptions all the way. So she's an Ackerman. And her fighting style is no doubt that of the Ackerman clan. It's not a fighting style that lends itself well to friendly sparring. As her father tells it, in generations past, the Ackerman clan was a warrior clan, serving as soldiers and bodyguards. Their techniques are designed to kill. In her spar with Kenny years ago, he omits offensive moves, using only defense and counters. And even then he gave her a hard time.

"So you do fight."

Mikasa, ever the conscientious driver, doesn't take her eye off the road. But her eyebrow does lift slightly, probably because she realizes that it's a statement, not a question. Her reply is a statement too. "Armin."

It's no surprise she figures it out. They're practically strangers with two mutual friends, one of whom seems dead set on denying the she fights. That leaves the other. "I promised him not to tell."

Slowing down at an intersection, Mikasa finds it safe enough to glance at her. "You saw me at the dojo. You would have found out even without his information."

"I didn't know you trained under Kenny."

"I don't. I train under his nephew, Levi," Mikasa replies, eyes back on the road. "Levi sprained his ankle some time last year, so he sent me here to train under Kenny. Their styles are different. Kenny's is purer. So I come here once a week to seek his tutelage."

Levi Ackerman? Now that's a name she knows too. He trains professional fighters, so his style is more of a fusion of other styles. They're also less lethal, since he has to abide by competition rules. So it's likely Mikasa's style takes after his. Which means, safe to spar.

"You train under Levi? Not your father?"

"There's a reason I'm adopted."

Mikasa throws it out just like that, so casually, that it takes a few seconds for her to register the implication behind the words. "Oh. I'm sorry. That was insensitive."

Mikasa shakes her head and shrugs. "You didn't know. It happened long ago."

Annie lets it grow silent after that, unsure if Mikasa is truly over the nerve she hit, or she's being polite about it. But a car ride is far quicker than a train and a bus, and soon she's seeing familiar roads and sceneries. It won't be long before they reach her place, so if she wants to say anything, she needs to say it now. Now while she doesn't sense any of that courteous front Mikasa always puts up. Now while they're both as open and real as they've never been.

"Fight me."

"No."

The answer comes before she even hears her challenge resound in the confines of the car. It comes so fast it's like Mikasa has been expecting her to say that, and the answer has been sitting on the tip of her tongue, just waiting to be spoken. It pisses her off that Mikasa doesn't even consider it. It pisses her off even more that Mikasa doesn't react in any way save answering.

"Why not?"

"I don't see any reason why I should fight you. I'm not interested in contests of strength, Annie. I know you're a great fighter, and I know you're skilled. I've seen Eren practicing his forms. You're teaching him well."

With the mention of Eren. Annie pounces on the opportunity. "But you are strong. Is that why he hides the fact that you fight? Because he's jealous of your strength?"

"He resents it." Mikasa seems to force the words out through her teeth and Annie swears she sees her knuckles tighten on the steering wheel just briefly. But then Mikasa sighs, and her voice loses the edge. "He resents it, and my protectiveness. For me, it's only a matter of course to protect those I love. For him, it's a burden."

She's hitting a lot of nerves today. Her desire to fight Mikasa even seems rather petty in the face of whatever issues Mikasa has with Eren. Is it just a sibling thing? Or does it run deeper than that? Without siblings of her own, she can't really tell. But the heaviness surrounding Mikasa does suggest she's been privy to something she wouldn't normally be privy too. So it falls to her to not make light of the situation. She may not know much about Mikasa, but one thing is clear to her. Because they're similar.

"Mikasa." A twitch is the only sign Mikasa's listening. But really, in the small confines of the car without even the drone of the radio as distraction, there isn't much else for Mikasa to listen to. "I may not like you, but I respect you. I've known who you really are the moment I saw you for real in Eren's house. You're strong, and I think that using your strength to protect those you love is not wrong. Your intention is nothing but commendable."

Mikasa says nothing and Annie presses on. "It is because I respect you that I want to fight you. I've been made curious about your strength and now I can't stop thinking about it. It's not about win or lose, Mikasa. I just need to know. Whatever the outcome, I'll be satisfied to have traded blows with you."

The car slows down and she feels it pull to the side before she blinks and realizes that they've arrived at her place. Part of her is impressed that Mikasa remembers exactly how to get here without a single reminder from her, the other part refuses to leave the car until she's done talking and she's gotten an answer. She knows that if she leaves this here, the moment she steps out and closes the door, it'll only get buried and when they meet next, Mikasa will pretend this conversation never happened. Mikasa pushes the gear into Park and pulls up the hand brake.

Annie feels a smirk tugging at her lips. "Fight me, Mikasa. Just once. Fight me and I promise I'll never bring it up again. Eren doesn't even need to know."

The wait for Mikasa's response feels longer than it probably is. She watches Mikasa's fingers drum on the steering, watches the rise and fall of her chest, and when Mikasa sighs and glances at her, she knows she has it in the bag.

"Alright. Come by Thursday. I'll ask Kenny to let us use the dojo."

She doesn't remember how they part after that, but running up the stairs to her unit, she does remember having agreed to dinner with Eren on Thursday. Fishing out her phone from her pocket, she quickly texts him to cancel it.

End Note: Story and chapter title taken from the song Wicked Game by Chris Isaak. This song is one of a few songs that I listen to while writing this fic. I particularly enjoy the covers by The Coves, Daisy Gray, and Gemma Hayes.

Comments and feedback much appreciated.