Author's Note: Got this idea from my friend when she told me Hajime revealed what Mikasa's like on her period in an interview, so I had to start writing XD Enjoy! And yes, this takes place during the Cadet training, before Eren becomes a titan. This is both a humor but also fluff oneshot. WARNING to any male readers, this does have quite a lot of graphically described period details.

It was early in the morning. Mikasa was sleeping in a bit in bed. She was curled up, her hands clutching her stomach firmly, her face expressing discomfort.

She also felt extremely tired, and couldn't bring herself to move. Her sleep was interrupted by a sharp, searing pain in her abdomen.

She gritted her teeth, giving a small shaky breath. When the pain only persisted, she curled up tighter. "Shit...", she hissed out, grimacing painfully.

"Mikasa? You okay? You've been groaning all morning", Sasha asked, she was awake and getting dressed. The girls shared a dormitory naturally, across from the boys.

"I'm fine..", Mikasa sat up, a hand still clutching her stomach. This horrible fatigue feeling wouldn't go away either.

"You barely eat, no wonder you got a stomachache!", Sasha pointed out. Mikasa felt her eye twitch, irritation setting in now.

She shook her head, not answering as she got up. Her bladder felt like it may burst all of a sudden, and she went into the bathroom to confirm her suspension. "What's up with her?", asked Sasha, confused. "Seems like Aunt Flo's in town", Ymir grinned. Krista frowned.

"Do you have to be so crude about it?! I'm sure the poor girl isn't feeling well! We've all been there!", Krista defended.

Inside the bathroom, after relieving her bladder, Mikasa saw blood in her underwear. Heavy blood. She often got it really heavy, and that didn't make it easier.

After getting a shower and using a pad, she brushed her teeth. Next, she heard a knock on the door. "Mikasa? Sweetie, are you okay?", came Krista's voice, sounding concerned.

Mikasa sighed, she knew Krista was just trying to be nice but there was no way in hell she could erase the glare from her face.

The girls waited, and finally Mikasa opened the bathroom door, dressed. She had the most coldest glare on her face.

It made everyone flinch except for Ymir and Annie. If looks could kill, all the girls would be dead.

"Where's my scarf?", she asked, her voice coming out more like a growl. The girls all froze up, panicking.

"Oh, right here!", Sasha held it up. Mikasa walked over, and took it. She silently wrapped it around her neck, pulling her newly cut short hair out from it. She had just cut her hair a few days ago, after Eren suggested it for her own safety in training.

She then quietly exited the dormitory, shutting the door behind her a bit loudly. "Yeesh...", Ymir commented.

"Count yourselves lucky, at least she didn't go beast mode on us", Annie said, as Krista remained worried.

"Hey, we can't badmouth her! We're all girls here! We all get moody during this time of the month! Remember what you did to Connie, Ymir?", Krista pointed out.

"True", Ymir admitted. "And you Annie! You mouthed off to our superior!", Krista added. "Can't say I remember", Annie scoffed, avoiding eye contact.

"Hey, all I do is sneak chocolate! I never attack anyone!", Sasha piped in. "You steal food too, then again that's normal for you", Ymir commented.

"Me too! I...one time I hit Ymir...", Krista confessed, grimly. They all starred, surprised. Ymir scoffed. "Pfft, please you mean that little love tap? Sweetie, I didn't even feel it", she said.

"I think its for the best we stay out of Mikasa's way", Sasha admitted.

Mikasa exited the hall, and walked passed Armin and Eren, who were heading to breakfast. "Morning Mikasa", Eren greeted, as Armin yawned.

Mikasa simply walked passed them without a word. Eren blinked, while Armin also woke up more just from that.

"Looks like its that time of the month...", Armin stated. After all, the three have known each other for six years now. Mikasa started getting her period at 11 years old...and it was a very embarrasing and difficult time for her actually.

It had been after the titans broke in, and for that brief time, the trio were living on their own as orphans. So Mikasa could only turn to two boys for help at the time.

Eren actually found himself thinking back to that time.

Four Years Ago

"Hey Eren, I got us some bread!", Armin said, looking relieved. He entered the small cabin the trio were staying in.

There were two cots inside it, one that Eren and Armin shared, while Mikasa had her own. They had enough blankets to stay warm thanks to Hannes, along with a working water bathroom, but otherwise things were tough.

They couldn't join the Survey Corps for another year, so for now they had to simply survive. Take it day by day. No family was willing to foster three orphaned children, so they were on their own.

Hannes did check by weekly to make sure they were all right, and brought them medical supplies when needed.

Eren was awake, gazing at the key he had around his neck. He tucked it under his shirt, as he took a piece from Armin.

"Thanks, I'm starving", he admitted, taking a bite. "I was able to get enough..Mikasa's still asleep?", Armin paused then.

Eren looked over at the cot, where Mikasa remained fast asleep despite it being afternoon already. She was curled up in a fetal position, her blanket wrapped tightly around her, wearing her red scarf.

"Yeah, she hasn't woken up yet...", Eren answered, worried. Armin approached her, and felt her forehead. "She doesn't have a fever...", he confirmed.

"She's probably just exhausted...", Eren said softly. Armin nodded, as he set Mikasa's bread on the corner of her cot, and sat with Eren.

As the boys talked for a few minutes, quietly so they didn't disturb the sleeping girl, their conversation was interrupted by a low groan from Mikasa.

She turned over, facing them as she curled up tighter, whimpering against her scarf. The boys tensed, not knowing what to do.

They had never seen her like this before. "Nightmare?", Armin guessed. Worried, Eren got up and approached her. He gently brushed her bangs back.

"Mikasa...?", he whispered softly. To his surprise, her eyelids lifted weakly. She sat up quietly, looking out of it.

"You okay?", asked Eren worriedly. Mikasa remained quiet, she shifted her position a little bit..her face then became a bit flushed.

"Can you both...leave for a few minutes?", she asked then, her face pink. Eren and Armin both blinked, confused.

Eren especially was stunned...after all, Mikasa clung to him like a puppy ever since he rescued her. "Please..", she added sharply.

"What's wrong? Tell us!", Eren demanded then, worriedly. "I SAID LEAVE!", Mikasa snapped then, surprising them both. Eren flinched, shocked.

The boys exchanged worried glances, but nodded. "Yeah sure...", Armin said. They exited the cabin, shutting the door behind them.

Mikasa exhaled shakily, very red now. When she sat up, she felt..wetness between her legs so she was under the impression she had wet herself in her sleep. Which she found odd...since she never had that issue, even as a toddler.

She also grew worried she may be ill...maybe some type of bladder infection. She had been too embarrassed to outright admit this to Eren and Armin, so that's why she forced them to leave.

It was times like this...where Mikasa needed a mother. If only her mom was here...or even Auntie Carla...but she was on her own.

She got out of bed, and went into the bathroom. But as she checked...what she saw in her underwear wasn't urine stains. It was...red. Like blood.

Outside the cabin, Armin and Eren continued to wait. "Man...what got into her? She never snapped at me like that before", Eren complained, while Armin was thinking.

Suddenly, both boys jumped hearing Mikasa cry out. "Mikasa?!", panicked, they both ran back in.

Eren and Armin opened the bathroom door, to see Mikasa was standing in the small walk in shower, leaning against the wall. Her breathing was heavy and frightened, and both boys saw the blood...since she was only half decent.

Feeling herself grow even redder and more embarrassed, despite the terrified state she was in, she yelled.

"D-Don't look!", she cried, flushed. "Mikasa, you're bleeding..!", Eren started to approach. He felt his heart sink...was she injured? Or sick?

It freaked him out even more knowing where she was bleeding from. "Wait..Mikasa, here!", Armin quickly grabbed a towel, so she could cover herself up.

Grateful, Mikasa took it and wrapped herself up, trembling hard.

"What happened? Did you hurt yourself?", asked Eren fearfully, as Mikasa shook her head. "I..I don't..know..I...I thought I had...peed but...it was just..blood...", she replied, shaking like a leaf.

"Do you have any pain?", asked Armin worriedly. "No I...wait..yes...ooooh...!", Mikasa suddenly grimaced, clutching her belly as she sunk down into a sitting position as she felt sharp pains in her stomach.

Eren was white as a ghost at this point...he legit was scared his friend was dying. "Armin..! Do something! Go get Hannes, anyone!", Eren ordered, as Mikasa continued to grit her teeth and groan in pain.

"W-Wait...hold on..Mikasa, is it your stomach?", asked Armin softly then. Mikasa gave a shaky nod. "Blood...your stomach hurts...I think I know what's wrong", Armin said then.

"What?!", asked Eren, panicked. "I...well, my mom talked about it briefly before she died...its something all women get...its called a period I think...", explained Armin.

"A period..?", asked Mikasa shakily, as her cramp eased up a bit, allowing her to breathe. "Yeah...basically when a girl starts to mature, anywhere between the ages of 9 to 12...they bleed from their...um...", Armin hesitated, going pink.

"Right...go on", Mikasa spared him the embarrassment of saying the word. "Their you know...once a month...they also get stomach pains, and are pretty tired and irritable too", Armin continued.

"For how long..?", asked Mikasa weakly. "I think just a few days...here", Armin cut the cloth from the towel then with a pair of scissors.

"Use this for now...to keep the blood contained", he said. Mikasa gave a shaky nod, taking it. Eren bit his lip, still white.

"Wait so then...she's okay?", he asked, as it all sunk in. "Yeah, I'm pretty sure...", Armin nodded. Both boys knew without saying it...Mikasa's parents died before they could give Mikasa 'the talk'.

Same for Eren...Armin was the only one of the three who had knowledge about this type of stuff.

Eren exhaled in relief then. Mikasa noticed this. She bit her lip then, tears sparkling in her eyes. Eren panicked.

"Mikasa, hey it's okay..! Don't cry...", he said softly. "I-I'm sorry Eren...for snapping at you like that...you're so worried...", she sobbed.

Eren's eyes softened. He moved closer to her, and gently offered her a tissue. "It's okay", he assured her gently.

Mikasa sniffled, she took it. "Thank you...", she said. After getting a shower, and getting dressed Mikasa spent the rest of the day practically mute.

Present

Ever since then, Mikasa always went mute when on her period. Although, she didn't need to speak. Her glares were enough to make anyone back off.

For five days straight she refused to speak to anyone, even Eren. And that hasn't changed at all. Breakfast was a bit tense. Mikasa refused to speak, as she ate quietly.

Eren cleared his throat, as Jean starred blankly at them. He leaned in a bit at Sasha. "Hey, did those two have a fight? What's the deal?", he whispered.

"Oh, Mikasa just has her period...", Sasha began to answer. Jean flinched, looking freaked out and instantly regretting he asked, as Mikasa suddenly stood up.

Everyone froze, and as Mikasa walked away from the table, a small group of trainees parted like the red sea for her as she stormed passed them.

"Hey, where you going?", Eren asked after her. She gave no answer, and left. "Scary...", Jean muttered. "It's always been like that...since we were kids", Armin admitted softly.

Outside, Mikasa started training early. She went for a long run across the area, and after the fact she retired in the basement to train some more.

After doing several sit ups, her body began aching more than usual. She cursed under her breath, irritated as she stopped.

As she went to get up, she winced, hissing in pain. Gripping her stomach, she sat down, catching her breath.

The pain persisted, and she gritted her teeth, dripping in sweat. She was so consumed by the pain, she didn't hear Eren come in.

She felt someone place a cool, wet cloth against her forehead. Her eyes opened, to see it was Eren. "Mikasa, take it easy today...I can see you're in pain", Eren told her worriedly.

Mikasa didn't answer him. She went to stand up, but winced. "Mikasa! Stop being so stubborn!", Eren yelled, getting frustrated with her now.

"Look, I already let our surperior know...he said you can take it easy today, in fact thanks to your grades and score, he said you can take the day off", Eren let her know.

Mikasa again, was silent. She stepped forward, but then another sharp cramp seized her. She gritted her teeth, and collapsed to her knees.

"Mikasa!", Eren hurried to her side. He kneeled down in front of her, grabbing her shoulders gently but firmly.

"Enough! Knock it off, you're just going to make yourself feel worse!", he yelled. Mikasa remained mute, looking down.

Frustrated beyond belief, Eren snapped.

"TALK TO ME, DAMN IT!", he yelled. Mikasa flinched, snapping out of it slightly, looking at him. Eren exhaled.

"Eren...", Mikasa said, she trembled a bit. Eren froze. "Sorry...I..didn't mean to yell..just...why? Why do you close me and Armin off when you're like this? The other girls don't go completely mute...", he asked, his voice softer.

Mikasa swallowed hard, before finally speaking. "I just...get so..irritated when this happens. I'm terrified I'm going to bite someone's head off if I open my mouth...like I did to you..", she revealed then.

Eren gawked at her. "Mikasa..what the hell? That was..years ago, we were kids! I forgot about that already...you even apologized", he pointed out, worriedly.

Mikasa bit her lip. "You were so worried..and I just...screamed at you...I never wanted to make that mistake again...", she explained. Eren sighed softly.

He took her hands then, helping her to her feet. Mikasa blushed slightly at the gesture. "Mikasa, you're over thinking it. I'm not gonna force you to be chatty, but...if you need to talk, don't bottle it up..", he soothed her.

Mikasa gazed at him. "Eren...", she said. "C'mon, you should be resting...let me at least take you to your room", he offered.

"Okay", Mikasa nodded, as the two held hands and went upstairs. Once Mikasa was settled into her bed, Eren had gotten her some water, and sat at her bedside.

Mikasa bit her lip. She moved a bit then. Eren blinked. "Are you okay?", he asked worriedly. "Yeah...Eren..can you..um...lay beside me? Like when we were kids?", she asked him, blushing harder.

Eren turned red at the request..when they were kids, Mikasa often crawled into Eren's cot with him, and they cuddled.

But..things were different now. They weren't kids anymore. "S-Sure...if you're okay with that...", Eren replied gently.

He crawled into bed with her. Mikasa shyly nuzzled against his chest, exhaling softly. Eren turned redder, feeling her breasts pressing against him.

"That...okay?", asked Eren a little awkwardly. Mikasa blushed. "Yes...", she answered, as they cuddled a bit closer.

Eren felt his face turn redder by the minute...but then he blinked. Mikasa's eyes had closed..she passed out. She was completely worn out from her period.

Eren exhaled, relaxing a bit. He gently stroked her hair, as she remained fast asleep in his arms. Armin peered in quietly.

He gave a sly grin, winking at Eren. "Oh shut up", Eren mouthed quietly at him, so he didn't wake Mikasa.

As Armin left, Eren smiled softly, as he gazed down at her sleeping form. He just realized...how beautiful she was.