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Sayu was bored.
It was a nice day out and Sayu was bored.
Now, one may ask themselves, what seemed to be the problem? Summer vacations had just started, the sun was shining, children were out in the streets celebrating the end of the school year. Well, Sayu would tell that someone that they were dead wrong! She had every reason to be moping dramatically on the couch, sighing repetitively without a purpose and without doing anything about it. Her mother had tried to cheer her up, but it was hopeless. There was nothing to be done. Sayu was sulking.
You see, Sayu had… homework. She had homework to do during the summer. Because she had barely passed her maths exam, her teacher had suggested that she do some work during the break, and her mother being her mother, and also being the mother of the outstanding, amazing, terrifically performant Yagami Light, had immediately adopted the idea with the passion of a thousand burning suns. So here was Sayu, during the summer, with homework.
The worst thing was that her best friend, Sayaka, was in France with her family. She had left Japan the same day that school ended, and she was now having a blast in Europe, that traitor. And she was. Constantly. Posting. About. It. What a way to remind Sayu that she was missing out on her summer! She was crying tears of blood over here!
She laid on the couch upside down, her notebook full of quadratics discarded on the floor in front of her. She just didn’t get it! At all! And who the hell was Bertha??
It’s not like she could ask Light, either. He would surely know how to help, and he really did have a talent for explaining things in a way that made sense—a talent her teacher severely lacked, evidently—but recently, he’d been busy. Which was normal, she guessed, his university entrance exam was nearing—but damn if it wasn’t super inconvenient! What was she supposed to do now, learn quadratics all by herself? As if!
It didn’t help that, however normal her brother’s recent business was, she couldn’t help but feel like there was more to it. It was totally distracting her! All in all, there was no place for maths in her head. The only connections that were happening were-
What if Light had a secret girlfriend? What if Light was secretly sneaking out to meet with his secret girlfriend while pretending to go out to study? What if Light secretly joined a gang? Oh, or what if Light was secretly auditioning to join a boy band?
She really wanted to know.
Well, it’s not like she could just ask him.
But… Well, Light wasn’t home. A quick glance towards the kitchen confirmed that her mother was busy making dinner, having long since given up hopes of convincing Sayu to do her work today. And of course, her father was off doing who knows what, as usual.
Sayu could just find out herself! If she could just take a quick glance through his room, then surely…
She grinned. Looks like she had a plan! She quickly set herself straight, ignoring the dizzying feeling of every single one of her blood cells rushing down to her legs to kick her notebook out of the way and rush up the stairs. She heard her mother sigh from her place in the kitchen and giggled to herself. Of course, Sayu had tired her out for the day. Like the barely-remorseful but perfectly adorable daughter that she was, Sayu ran back to the kitchen to grab herself a glass of water, hugging her mother as she passed by. Sorry, mom, but this is super important! She climbed back up the stairs with purpose. All her family was busy, now. She should be free to roam the forbidden realm of her older brother’s bedroom for at least a little while.
As she got closer to the door, she made sure to keep her steps quiet so as to not alert her mother of her suspicious activity. She turned the handle slowly, listening for any sound that indicated she was heard, but she could only hear the faint cluttering of pots and pans. Very nice, very nice. Sayu smiled to herself, feeling like a spy from one of her TV shows. A single piece of paper fluttered to the floor with the air current created by the door, and she picked it up with a flicker of curiosity.
Turning it around, Sayu saw that the paper was blank. Boring. She entered Light’s room and threw it in the trash can.
Looking around, Sayu saw that her brother’s room was just as plain as it had always been. Truly, it seemed like he didn’t have a life outside of school—she simply couldn’t understand him at all! She’d never even seen him bring home a friend, that’s just how much of a loser nerd he was. Sure, their parents were proud of him, but how did he manage? Wasn’t it super boring to only do schoolwork at all times?
Well, Sayu supposed that if Light really had gotten himself a secret girlfriend, he’d finally have something to do with his life! Maybe he’d finally graduated from loser school! She really hoped that was the case, anyhow.
Anyways, Sayu decided that she would definitely find something cool now that she was here. And so began her search, discarding her half-empty glass on Light’s desk. The first step, obviously, was his bed. That’s where she kept her secret diary, after all—right between the frame and the mattress. There was nothing of note there, though, not under the bed nor under the pillows. She huffed disappointedly and redid the covers as best as she could. Which was, admittedly, bad, but whatever. If Light had any complaints, he could whine about it. She knew nothing much would come out of it—she already had homework to do during the summer, what more punishment could possibly befall her?
Anyways, next step: the bookshelf. She’d recently watched a series where the protagonist’s girlfriend has hidden the key to some secret base between the pages of a book. To be honest, she hadn’t really understood the plot of that story at all, but she’d still finished the series because the male lead’s best friend was played by Hideki Ryuga. Truly, it was a crime that he didn’t get the main role, but still! He’d been as charming as ever, even in a secondary role.
Flipping through random books on physics and chemistry and biology and other stuff she didn’t care about, Sayu was once again faced with the fact that her brother had no life. Not a single fictional story—except, of course, the classics Light’s teachers assigned him. Not a single novel! Not a single romance book, or science fiction, or fantasy! Sayu would’ve died a long time ago!
She had started to lose hope by the time she reached the thick black books on the bottom shelf. When she pulled the first heavy book out of its place amongst the others, though—not without a little struggle that she’d keep between that book and herself for the rest of eternity—her eyes widened as she found several magazines hidden within the fake cover. Was this it, then? The big secret she’d been looking for?
She pulled the first booklet out of the case with a bated breath, and promptly burst out laughing.
Oh. My. God!
Her brother wasn’t a completely hopeless loser, after all? He really did show interest towards women! There was hope for him still—and this was all the more evidence for Sayu’s theory. Maybe he really was running around the town with a secret girlfriend. Or at least, maybe he’d like to be…
Well, now she was only more determined to find the evidence of that mystery girl’s existence. She—and her mother and father—really had begun to believe Light was just… completely asocial. He’d never shown much interest in other people his age, after all, so it was only natural. But now! Now! Sayu’s poor heart started to believe, after all this time, that perhaps he wasn’t as much of a hopeless recluse as she had believed. Oh, what if she became an aunt? Wouldn’t that be so crazy! With a bright grin, she placed the book back on its shelf, careful to make it seem as if she’d never touched it at all.
Don’t worry, Light, your secret is safe with me!
Naturally, the next step was the desk.
It seemed like a completely normal desk, honestly. There were a couple pencils in an old glass, books lining more shelves on the wall and a pristine computer. She wouldn’t even try to get into the device, knowing there was no hope of her ever succeeding at opening it. Of course, Light would’ve put some super complicated password so only he could access it—that was just how he was. Maybe, and she shuddered at the thought, he’d even used a quadratic equation for the code! Nope, no way was she getting near that thing! Her life depended on it!
Mindlessly, she reached for the first drawer on her right and pulled it open. Looking inside, it seemed nothing was amiss… Except… There, at the back, was that paper peeking out of the bottom of the drawer? How sloppy—Light definitely must’ve been in a rush, he usually would’ve never made such an obvious mistake. Grinning at the thought of a secret journal of sorts, Sayu tugged on the paper once, twice, and it was freed from its position. Disappointingly, it only showed a bunch of maths formulas that she didn’t know. She huffed.
Obviously, though, for the paper to have slipped from the pile and gotten stuck in such a way, there had to be a fake drawer of some sort, right? She’d seen them often in spy movies! How exciting! To test her theory, she knocked lightly on the back of the drawer, and just as expected—it was hollow. Now she really felt like a detective!
Alright then! All the more reasons to get to the bottom of this! Using a ruler that she grabbed on Light’s desk, she slid it between the bottom and the side of the drawer, moving it little by little… After a while of messing around, the false bottom moved slightly. Yes! There was a bright flash of light, a sudden warmth…
“Ack!” she shouted in surprise, recoiling away from her brother’s desk, which was on fire. Flames licked the wood hungrily, starting from that very drawer she had pulled open but spreading over to the rest. Panicked, she grabbed her glass of water and splashed it onto the fire. It did little to help, only stopping the flames for a brief seconds before they engulfed the space again.
“Mom!” Sayu screamed. “Mom!!”
She must’ve sounded panicked enough—and rightly so!—because it took barely a second for her mother to hurry up the stairs, calling her name in a worried tone. “Sayu? Sayu, what’s wrong?”
Naturally, she headed for Sayu’s room first, but quickly spotted her daughter through her son’s half-opened bedroom door. And with that, the fire.
“Oh my g- Sayu, what the hell happened?!” The woman quickly rushed into the room, looking at the flames in absolute bewilderment and fear before she snapped her mind back onto the task and started dragging her daughter out of the room. “Quick, go grab a pot from the kitchen and fill it with water!” And she herself rushed down to grab the fire extinctor, which had luckily been well maintained, courtesy of her husband. She had never believed it would be of use, but now she thanked the heavens for his foresight.
She used the extinctor on Light’s desk, and then used the water Sayu had brought her to clean the foam off. Breathing a sigh of relief as her son’s desk was finally free of the flames, Sayu’s mother turned a stern gaze towards her daughter.
“Sayu. Would you mind explaining why your brother’s desk was on fire just now?”
Sayu was still looking at the wet ash from half of the desk with wide eyes. “U-uh, I- I don’t… know? It just…”
Her mother raised an eyebrow. “Sayu, don’t lie to me now. Did you somehow set that fire? You were the only one in the room.”
“I don’t know! I just opened the desk and then it was on fire!” Sayu shrieked, her mind reeling from the suddenness of it all. Her mother sighed.
“We’ll have to replace that desk… Oh god, it’s not like Light needed anymore stress now, he’s already got the exam…”
She mumbled a few more words, sending one last disappointed, tired look towards her daughter before saying: “We’ll talk about this later, alright? I’ve got to call your father…”
She left the room, and Sayu looked back at the ashes with wide eyes.
What the hell.
She approached the desk to see the damage done by the fire. How did this happen? What did Light even keep in his desk for this to happen? Fireworks? Was it drugs, did her brother do drugs? She brushed her fingers against the charred end of what remained of the desk, noting the scorch marks on the wall and floor. What a mess…
Between the rubbles, a piece of darker black caught her eyes. It was small, maybe the size of her palm, but it shone strangely in the middle of the wood dust. She reached for it, picking it up. It seemed to be… a piece from a book? How did it survive the fire? She guessed the cover did look strangely leathery, but still… She turned it over, noting the white streaks on the other side. Letters, maybe—Sayu could make out the faint shape of a D, and maybe an e after? She flicked the pages open, but most of them were a faded orange color because of the flames—any text on it obviously unreadable. She sighed and placed the remains of the book back in the soot. There wasn’t any use in such a ruined thing, after all…
In the living room, Sayu anxiously waited for her father and brother to come back home. She knew she’d definitely get scolded, even if she hadn’t technically done anything… Well, anything to start that fire, at least. She’d give Light hell for this if she ended up with more homework! She’d tie him down and force him to explain how to solve quadratic equations until she got it right! Obviously, that’d take forever, and she’d probably get bored… Whatever…
The front door opened.
“I’m home,” said Light as he came in, followed by the hugest, weirdest demon-like creature thing Sayu had ever seen in her entire life. Her jaw hung open as she stared at the thing, which both her mother and brother completely ignored. Oh god, was she going crazy? Was this a dream? She let out a low squeal of absolute confusion as the blue demon met her gaze and smiled disturbingly wide, showcasing a long row of pointy, crooked teeth. Light sent her a confused look, but before he could ask anything, their mother sighed as she approached to greet him.
“Light, darling, I’m so sorry… Your sister has something to tell you, doesn’t she?” she asked, sending a pointed look in Sayu’s direction. She let her wide eyes leave the demonic entity, which now seemed to be containing its laughter, and met her mother’s gaze for half a second before banging her head against the table and groaning. What the hell was today…?
“I set fire to your desk…” Sayu mumbled, hiding her face in her arms.
“What?” she heard Light reply instantly, sounding as bewildered as she had felt when his freaking desk caught on fire! On its own! She raised her head to glare at him. It was obviously his fault—it wasn’t her fault that he kept his illegal cigarettes in his drawer or something! “I’m… not sure what to say?” Is what Light politely settled on saying, looking between the two women with measured confusion.
“Yeah, well, maybe if you didn’t keep things that catch on fire super easily in your drawer, it wouldn’t have caught on fire!” she crossed her arms and stuck her tongue out at him, already defensive. She didn’t want any more maths, please, God!
Her father entered the house a few minutes later and immediately set a heavy gaze on Sayu’s frame, lying limp on the kitchen table with her gaze settled fixedly on the wall—-she was busy ignoring the dancing demon that seemed to be following her brother around. As soon as her father arrived, however, she knew it was over. There was nothing but maths and repentance in her future.
And that’s the story of how Yagami Sayu spent an entire summer solving quadratics with a huge blue demon towering over her shoulder.