Pairing: Eren/Mikasa

Setting: Harry Potter AU; Set in the beginning of their sixth year

Rating: K+

Words: 5187

Notes: I actually wrote this before the prompts were released; later in the same day Ashley told me what the prompts were so when I saw "crossover" I was like welp might as well just use this dumb thing I wrote up for the first of September. I told her that to which she told me the original prompt was supposed to be more Harry Potter centric but decided to make it more generic since someone would still write a Harry Potter AU. Which happened to be me.

I purposely avoided as many Harry Potter terms as I could to still keep it less "hey look at me I'm a crossover" but yes I enjoyed picking out houses for everyone and I'm sure you'll be able to guess whose where :3

October 9th - Crossover

"I think we're getting a little big for this," Armin said as he held up the worn cloak in front of him.

Eren yanked it from his hands, walking down the spiraling staircase of their house tower and draped it over his arm. "But it still works."

Armin snorted. "As long as no one looks at our feet."

Eren chose not to respond to that. His feet hit the main landing that led into the common room; he looked in seeing the never ending fire in the fireplace illuminating the otherwise dark room. No one was up, or up in the room at least which was good for them. All he needed was little tattletale first years giving them a hard time the first day back at school. "All clear," Eren said to Armin before looking up towards the staircase opposite of the one they had come down. Eren wanted to just go up and get her but he had hit his head one too many times on the enchanted stairs as they turned into a slide under his feet to try.

"Mikasa," he called, but not so loud as to alert every other female in his house that he was there; though he was pretty sure most all of them were used to it.

"I'm here, don't be impatient," she said, her slender form walking down the stairs. Like them she was dressed in her pjs with a bag over her shoulders, her bare feet padding against the wooden steps. She stopped in front of them, her arms crossed but a smile pulling at her lips. "Are we going to fit?"

"You sound like Armin," Eren said stepping down into the common room. "Don't under estimate the power of the cloak."

"Unless because of the shortness of the cloak," Armin followed him with Mikasa. "Professor Ackerman catches us and we get detentions before the school year even technically starts. We learned about six years ago that just because Mikasa is related to him means absolutely nothing for us. In fact it makes it worse, well, for you at least."

Eren turned around when he reached the house exit. "C'mon, when've we gotten caught?"

Both Armin and Mikasa opened their mouths to speak.

"I mean, during our first night ritual." He didn't appreciate the little faith but at the same time he understood. He couldn't even count on his fingers the amount of times he had detentions in his six years at school. "Are we ready, or are you just going to harass me until everyone wakes up?"

"Lead the way," Mikasa said.

Eren climbed through the hole in the wall as the large painting that served as their entrance way swung open. The coast looked clear but he wasn't risking it; the moment Armin and Mikasa stepped out he swung his cloak over them. They had to bunch together and hunch over to get the cloak to cover them but it worked.

"Thank you, Dad," Eren whispered with a grin.

Armin reached into the bag slung over his shoulder and pulled out a piece of parchment as well. "Another thank you to Dr. Jaeger; though I don't think sneaking out was quite what he had in mind when he passed these down to you."

Eren chose to ignore that as he pulled out his wand from his pocket; he mumbled the right words and the map came to life in his hands. There were a few people out on patrol, House Head Professor Ackerman being one of them, not that he never slept or anything to begin with. There were also a few prefects wandering about and House Head Professor Zoe as well, again another professor who never seemed to sleep. At least the other House Heads, Professor Ral and Professor Smith, weren't always lurking around at night. Though he wouldn't particularly want to get caught by Professor Smith; he could almost be as bad as Levi.

Eren started to lead the familiar way through the castle with Armin and Mikasa shuffling with him to keep the cloak over all their bodies; this really was a lot easier when they were first years. They had to get down the vast staircase three floors, past the charms classroom and past the restrooms on that floor, then it was far down an empty hallway that was filled with various types of study rooms but those were always monitored. It was a left at the end of the hallway and an old wooden door stood untouched all summer. Eren took a quick look at the map once more before pulling off the cloak from them.

"Thank God," Armin said, stretching his arms over his head.

Mikasa reached forward to open the door, ushering them all inside. The room was dark but it hadn't changed since the last time Eren saw it. Mikasa reached for the lantern off a nearby table as she pulled her wand out of her bag. Soon the whole room was illuminated from the small glass lantern while Armin spoke a silence charm over the door. Eren plopped down on the tattered old couch, tossing the cloak on the small table in front of him, and laying the map out to keep an eye on just who was on the floor with them. Mikasa placed the lantern next to the map before taking a seat next to Eren while Armin sat down on the nearby armchair.

"At least no matter how much we outgrow the cloak, this place never changes," Eren said, reaching an arm around Mikasa to tug her closer to him.

"That's because we're the only ones who know about it," Armin snorted. He tossed his legs over one of the armrests while he placed his head against the chair.

"As it should be," Eren said. "I double checked no one followed us out, not that Jean doesn't sleep like the dead to begin with."

"Sasha wouldn't wake up unless you placed bacon in front of her face so I didn't worry about her either," Mikasa said.

Silence settled over them as the light flickered in the lantern sending shadows moving all around them. It was strange to remember the first time they found this room, lost little first years too nervous to ask for help. It turned into a refuge and then a tradition.

"Sixth year," Armin let out a low whistle. "One more year to go after this. Can you believe it?"

"What I can't believe is how hard our classes are gonna be this year," Eren groaned as he reached down to the ground to pick up a pillow and put it on the couch before he leaned over to place his head on the pillow, laying across the couch. "All advanced classes? Give me a break already." He pushed his legs under Mikasa's as he stretched out.

"That's what happens when you're two years away from graduation," Mikasa said in that knowing tone that used to infuriate him. "Better get to studying and not copying off Armin."

Where he once might've snapped at her or gotten grumpy with her, she was borderline unbearable in their early years here with that know it all voice, he instead reached up to grab her around her waist and pulled her down against him. "Yeah? You gonna let me copy off of you instead?" She was already laughing before Eren started to wiggle his fingers against her sides.

Armin rolled his eyes but Eren still saw the smile on his face. "I liked you two better when you fought all the time." He pulled a pillow off the armchair he was sitting on and tossed it over at them but Mikasa reached up to bat it away before it hit them.

"When do your classes start tomorrow, Armin?" Mikasa yawned, laying her head down on Eren's chest while his hands came to rest on the small of her back.

"Too early," Armin answered. "And considering it's probably around 2am right now, I have class in about five hours."

"Want to go back?" Mikasa asked.

Armin shook his head. "And miss this? No way." He grabbed his bag up off the ground and pulled out a bottle. While it looked like something kids their age shouldn't be in possession of, Eren knew it wasn't that fun; it was essentially sparkling cider. Armin grabbed three plastic glasses from his bag too as he sat up in his chair to place them on the table. Eren reached down to Mikasa's bag pulling out the bag of small cakes he knew was in there. He pushed both himself and her up on the couch, adjusting so his back was against the cushions and Mikasa was seated between his legs, her back to his chest.

"It's officially the start of the year now," he said, watching Armin pour each cup full.

Mikasa opened the bag Eren had pulled out, holding onto two little cakes before placing the last one on the table for Armin. She passed a cake to Eren when Armin reached out to hand Mikasa and Eren their glasses.

"To another year," Armin said, leaning in to tap his cup against the others.

"To passing classes," Mikasa said.

"To not getting detentions," Eren snorted placing the cup to his lips and drinking down the sweet but bitter fizzy drink. He popped the cake in his mouth when it probably should have at least taken a few bites but it was 2am he didn't have the patience to sit and munch on the cake. He wasn't sure when exactly they decided to do this at the beginning of each year but it had turned into something they just did. While they didn't need the room to take refuge from the upper years anymore like they used to, they still liked to start their year here to remind them of how far they had come and as a good excuse to eat sweets late at night.

Eren placed his glass back on the table when he was finished, watching Armin drink down his and Mikasa still working on her cake. Eren wrapped his arms around her waist, pulling him back against her as his chin rested on her shoulder. He heard her breath hitch in her throat as she did; sure they had spent their entire fifth year fighting over everything imaginable but spent their entire summer actually together so Eren figured it was a fine trade off.

"We should head back soon," Mikasa said, carefully licking the left over glaze off her fingers. She leaned her head back against Eren's. "Before someone notices we're gone."

"She's probably right," Armin yawned as he pushed himself to his feet. "That's all we need detention on our first night back."

"I dunno," Eren said. "I think we've got a little bit longer."

Mikasa turned her head to look at him. "I think you're making excuses to avoid going to bed and start classes tomorrow."

"Well, yeah. Not everyone enjoys listening to professors drone on all day like you two do." A smile was pulling at his lips as he tilted his head down towards hers. "Besides, I don't mind it here, you know."

She opened her mouth but Eren didn't give her a chance, he pressed his lips against hers not quite catching her off guard but enough to feel her small gasp against him. Eren could hear Armin groan again but he wasn't quite concerned with him at the moment; all he could focus on was Mikasa's soft lips moving with his. His hands gripped onto her waist wondering how it took him so long to see what was always right in front of him. Well, better late than never.

"Enjoying your time with my sister, Jaeger?"

The voice was certainly enough to make Eren nearly jump off the couch; if Mikasa wasn't sitting in front of him he probably would've; his blood went cold and his heart nearly stopped.

Standing at the door dressed in his long robes with green trim stood Professor Ackerman, and with those crossed arms and that scowl he looked about as happy to see them as they were to see him. Even Mikasa who lived with her much older brother went stiff.

"We were just-" Eren tried but Levi was not having it.

"Yes, just out of your beds far past curfew in a room you should not be wandering in and unsupervised. Out. Now." He pulled out his wand and sent out the lantern leaving them in the dark save for the light of his wand.

Mikasa grabbed the cloak and map off the table in one swift movement into her bag that even Eren who was standing next to her almost missed. Armin was the first one out with Eren and Mikasa trailing behind.

Levi shut the door as he left the room as well. "Move."

Eren felt like he was a first year again getting berated by his teachers…well, nothing really had changed save for he wasn't a first year anymore and the teacher wasn't just his best friend's big brother but his girlfriend's big brother who didn't know that fact until about two minutes ago.

"I never understood why you got caught up with these two, Arlert," Levi said, herding them out to the main staircase. "You at least have more brains then them."

"Brains don't mean anything if you don't have people you can trust, Sir," Armin said a bit meekly even though he was used to getting in trouble with Eren. Armin along with Mikasa rarely ever deserved the punishment given, since it was always Eren's idea or fault, but they still always took it with him.

"Hey, Levi! See you caught yourself some kiddies!" Eren could see Professor Zoe making her way down the hallway like it wasn't 2am in the morning but just a regular afternoon; her black and blue robes looking as tattered and well, burnt, as normal. "Oh," she said, her tone disappointed as she lifted the goggles off her eyes and onto her head to see better. "I suppose I shouldn't be surprised that it's you three."

"Jaeger, Ackerman, Arlert," Levi grunted, crossing his arms in front of them. "All three of you are going to meet me at 6am in the main hall. Oh yes, I'm very aware that's only in about three hours. You'll be helping me clean up some of the older classrooms. Without magic."

Eren couldn't hold back a groan; there wasn't a worse detention than having to clean with Levi, he was the worst damn clean freak Eren had ever met.

"Arlert and Ackerman, you can leave when Arlert has class in the morning. Jaeger you're staying until you have class."

"But that's not until noon."

Levi gave him an expression which distinctly said "that's the point".

"Why do I have to stay and they get to leave?" Eren grumbled, crossing his own arms against his chest. He wasn't mad they got off the hook some, Merlin knows they deserved that after everything he got them in trouble for but he did want to know why he was getting punished more.

"Because it's going to take me longer to get the image of your bratty face kissing my sister out of my head that's why."

Eren heard Professor Zoe snorting with laughter behind them.

"I don't want to hear it from you, Four Eyes. I'm taking these brats back to their House, watch the halls for me."

Professor Zoe mock saluted him before turning back the way she came.

"Move," Levi said pointing towards the staircase.

"Levi," Mikasa started her tone warning as she stood firm in her spot, her gaze narrowed at him.

"Oh no, you don't get any right to tell me anything until you get better taste in men. Here I had hoped that ridiculous crush you had on Jaeger for all these years would never amount to anything. He seems to have more sense than I realized. Walk before I make it two days of six am cleaning."

Mikasa didn't look like she wanted to back down but her cheeks started to heat up before she turned and followed in suit with Armin and Eren back towards the seventh floor of the castle. It really wasn't anything different, whether they were getting in trouble with Levi at school or at Mikasa's house, and it generally ended in cleaning. As long as he didn't tell Professor Smith or Pixis about this it would be bearable. Getting lectured by the head of his house was like getting lectured by his father or something, both guilt inducing and boring. Pixis wasn't so bad but God knows Eren had been brought to the headmaster's office too many times in his going on sixth year here.

"Alright, wake up," Levi snapped at the sound asleep painting. "Let the brats back in."

The woman in the painting didn't seem to berate them as well when she was jolted awake but if looks could kill. She swung open revealing the door to the common room. Eren moved to jump in and get away from the professor; he'd see him enough in just a few hours but Levi cleared his throat to get their attention again.

"In addition to cleaning, all three of you will deduct 10 points from your house starting you off with -30 points. I expect you on time in the morning." With that, he was gone.

Eren couldn't help but groan as he practically fell into the common room, Mikasa and Armin following behind. He was gonna hear from his house mates in the morning and probably from the others in his year in different houses too; who else would've been stupid enough to get points deducted on the first day of school. He felt a hand on his shoulder and glanced behind him to see Armin standing between both Eren and Mikasa.

He didn't look upset in the least, neither did Mikasa for that matter. "Well, I at least think it was worth it. Happy sixth year."

Eren snorted but a smile was pulling at his lips. Yeah, it was worth it.

It was still worth it even when he was on his hands and knees scrubbing Merlin knows what off the floor of what once looked like a potions classroom. He had the sleeves of his gray sweater and white button up rolled up above his elbows, his burgundy and gold tie tucked in the sweater so it wouldn't fall into the now murky water on the floor and his black robes long abandoned. The knees of his black slacks were already wet from the floor but as long as he could get away from this without being completely soaked he supposed he'd be okay with it.

For what seemed like the fiftieth time that minute, Eren pressed the soaked and soapy rag into the stain on the stone floor. Of course once Armin and Mikasa left, though Levi had to practically kick them out, Eren would get shoved in the basement, cleaning a room that hadn't been touched since before he was born; maybe since his mom and dad were in school here.

With a groan he dropped the rag and sat back on his heels. Levi was insane if he thought Eren was cleaning this whole room alone before noon. It already felt like hours since he was left alone and they only left at eight. Eren wasn't regretting the action that got him here, but he sure as well regretted getting caught. How did Levi even find them there? He had like some kind of sixth sense or something.

"Did you seriously lose us 30 points already, Jaeger?"

Eren turned his head to see Jean practically fuming in the doorway; yeah, he expected that. "Did you really walk all the way down here to harass me?"

"That is completely beyond the point! What the hell did you do!?"

"Give him a break," Connie said, who popped up behind Jean with Sasha by his side. "I heard Professor Ackerman busted them, there was no way to get outta that."

"Says you," Sasha said though she didn't look too mad when she reached over to playfully pull on Connie's black and yellow tie. "Even your house is ahead now."

Jean whipped his head around. "Busted them?"

"Yeah." Connie was trying to slap Sasha's grip off him. "That's what Bertholdt told me and Marco when we were going back to our common room after breakfast. It was Eren, Armin, and Mikasa, ten for each. Why do you look so surprised, Jean? It's not like it's uncommon." He looked over at Eren. "No offence."

"None taken," Eren shrugged.

"Who told Bertholdt that?" Jean said, still not looking very pleased; not that he ever did.

"Reiner did."

"How the hell did Reiner know that, he's not in either of our Houses."

"Ymir told him this morning when they left their common room for breakfast."

"Ymir found out from Historia of course," Sasha added.

Jean looked like he had no idea how to follow this story anymore and Eren couldn't really blame him; he didn't even know news traveled this fast between their year. Inter-House gossip went fast he supposed.

"And how did Historia find out?" Jean asked, crossing his arms against his chest.

"Professor Zoe maybe," Eren said. "She's Historia's House Head, and she was there when we…you know." It was embarrassing enough; he didn't feel like going through it again.

Sasha shook her head, though she looked like she was trying not to laugh. "No, Annie told her. They're in the same house after all and Armin told her when they had class together this morning."

Armin. The root of the gossip. Eren just rolled his eyes; it wasn't like it wasn't gonna get around when everyone woke up and saw negative 30 points right off the bat.

"Whatever," Jean said turning on Eren again. "Just what the hell did you drag those two into, Jaeger?"

"And why do I have to drag them into anything. Last I knew, my two best friends were very willing to go out after curfew because, yes, that was what we got caught doing."

"Then where are they?" Connie asked. It was an innocent question, wondering why Eren was the only one punished but the explanation wasn't so innocent.

"They were here cleaning earlier, but they only had to stay for a few hours," Eren shrugged, hoping that would be the end of it.

"Then what did you do to get extra punishment?" Jean was smirking, that dumbass smug look on his face.

Eren just wanted to tell him just why Levi gave him that extra punishment to wipe that dumb look off but he knew Mikasa wouldn't quite like that. Armin and now Levi and Professor Zoe were the only ones who knew and Eren knew Mikasa valued her privacy from prying eyes. "Because it was Professor Ackerman, you know how much he hates me."

"Hate is a strong word, Jaeger."

Eren nearly fell back down to his hands to fake like he was still cleaning but Levi was already at the door, watching Eren so he didn't even bother.

"You just irritate every fiber of my being."

"I suppose that's better than hate."

Levi turned to the other's standing by the door, watching him with wide eyes. "Don't you have somewhere else to be." It wasn't a question.

Jean, Connie, and Sasha all hurried out of Eren's sight without another word.

"I really wish I had that power on them," Eren said.

Levi scoffed looking around the room but he didn't say anything to why it didn't look spotless. He merely walked over to the old wooden desk at the front of the classroom and looked down at Eren, his robes not even brushing over the water on the ground. "How long."

"How long what, Sir? Have I been cleaning?"

"How long have you been dating Mikasa."

Eren thought his heart was going to stop as he stared up at his professor; this was not something he ever wanted to talk about with Levi of all people. "I don't really think this is an appropriate student/teacher discussion."

"I've known you since you still wet the bed, kid. I suggest you tell me."

Eren knew he wasn't getting out of this, not that he could get out of anything with Levi ever for that matter. "I dunno, the beginning of the summer I guess."

Levi arched an eyebrow. "Despite the fact you made her upset countless times last school year?"

Eren sighed, dropping his hands onto his lap; he should have known this was coming. "I was frustrated. I didn't understand why the girl I grew up with suddenly meant much more to me than just one of my best friends. Why I couldn't even take it if she wasn't near me, why her smile sent my stomach in my throat, or why her touch had me practically jumping out of my skin." Eren looked up to Levi whose expression hadn't changed at all. "Why she suddenly turned into the prettiest girl I had seen, and why other people noticing that fact made me want to punch them in the face."

"Which you did. A few times."

"It didn't make her any less upset with me," Eren said. "Nor did it make me any less angry. Armin was the one who just told me to go talk to her about it, probably because he was tired of being stuck in the middle. I did, and there you have it. I've been significantly less angry and she's been significantly less upset with me."

Levi watched him for a moment. "It doesn't change the fact how much you've upset her in the past."

"Yeah, don't have to tell me that." Eren reached up to run a still slightly wet hand through his hair. "I'm trying to make it up to her, to treat her right."

Levi pushed himself off the desk and walked over to him, water splashing slightly on the ground. "I was waiting for you to get some sense in your head, kid. Don't guilt yourself to death, anyone with eyes could see you've always cared about her. Just don't let yourself forget it."

"Yes, Sir."

Levi turned to the desk, his back facing Eren. "Now get out of here. She's waiting for you by the stairs."

"Uh but it's not…?"

"Are you seriously questioning me on this?"

"No, Sir." Eren scrambled up to his feet and headed right to the door. He was up cleaning since six in the morning; he would take what he could get.

"Jaeger."

He halted in his tracks, turning back to his professor who was watching him again.

"I don't think I have to let you know what would happen if you broke my sister's heart."

Eren swallowed the lump in his throat. "Got the message loud and clear, Sir." He didn't wait to hear anymore. The rest of the stone hallway was empty, most people in class or at lunch by now, but there was one person waiting underneath one of the torches on the wall right in front of the staircase leading back up. She was right where Levi said she would be; Mikasa was wearing the same sweater and skirt he saw her in when she left, knee highs covering most of her legs. She had black robes draped over arm but considering she was wearing hers, he knew she must've grabbed his for him.

"The wicked stepmother let Cinderella out early," Eren said as he walked up to her. He looked up the stairs before leaning in to press his lips to hers in a quick kiss.

"You must've been on good behavior then. Scrubbing those floors on your knees," she said, gesturing to the wet marks on his pants; Eren didn't miss he red tint to her cheeks though.

Eren snorted as she helped him slip on his robes over his uniform before she handed him his wand as well. "I don't care what kind of food they are serving in the Great Hall, I'm starving."

"Armin already has our seats saved," she said turning to walk up the stone steps and back to the main floor of the castle. She glanced back at him as he followed her. "What did Levi say to you?"

"Who says he said anything?"

Mikasa gave him a look that would wipe away any doubt Mikasa and Levi were related.

"He threatened me if I ever hurt you, you know, the typical big brother talk. It was a little more intimidating cause he can flunk me on top of making sure I never walk again."

Mikasa tried to cover her mouth as she laughed but it didn't do her any good, except make her look cute. "I'm sorry."

Eren waved her off as they reached the top of the steps; the front hall being much fuller than the basement hallways. "I'm used to it from him by now." Eren reached over to grab a hold of her hand, lacing his fingers with her; their sleeves on their robes were long enough anyway. He tried to lead her to the Great Hall just to finally get some peace, quiet, and food and the open doors were right there, he was so close. Yet when a tall body stepped in front of him blocking them both from entering the hall, he knew it was not going to happen.

"Hello Eren, Mikasa," Professor Smith smiled, his hands behind his back as he looked down at them. "I take it you're going to meet Armin inside? I saw him sitting alone so I assumed you two were on your way."

"Ah, yes, Sir," Eren said, carefully removing his hand from Mikasa's.

"Good. I had a talk with Professor Ackerman this morning, and thought I would talk to you three too. Do you mind?" He was still smiling but Eren knew there was absolutely nothing he could say to oppose his House Head.

"Not at all."

"Wonderful, lead the way." He stepped aside and Eren got a good look at Armin, watching them with weary eyes; he knew what was coming too.

Eren suppressed a groan as Mikasa walked in front of him with Professor Smith following behind. Great, he cleaned all morning under Levi, and now while he was trying to eat, he'd get a guilt trip from Captain America himself.

Armin scooted over so Eren could sit down, Mikasa taking the spot on the bench next to him. Professor Smith sat directly across from them; Eren could almost see the lecture in his face. It would be a miracle if he got through this without falling asleep.

He felt a hand brush against his leg causing him to glance over at Mikasa, who was staring at Professor Smith with her usual calm expression, but Eren saw a twitch of a smile on her lips.

Okay, it was still worth it.