Chapter Text
Light is five years old when her parents first leave her home alone to watch her younger sister.
Souichirou’s at work. This isn’t a surprise: Souichirou’s always at work, and frankly, that’s where Light prefers him. If Souichirou’s at work, he’s not at home to awkwardly shuffle from the front door to the dining room, and from the dining room to bed, all without acknowledging the girls he doesn’t know what to do with. In her eyes, this is more than fair. After all, she doesn’t know what to do with her new father either. He’s not present enough to be a dad, and he’s got too much pride in his position for her to quell her little ACAB heart. So wishing for long hours at the office is the best she can do.
Sachiko, though. For Sachiko, she’s got notes.
Yagami Sachiko is a very big fan of having a ‘genius’ for a child. She was ecstatic when Light started walking early, talking early, even potty-training early. If there was a milestone to hit, you could bet your ass Light was ahead of the curve. While this was attributed with Light’s apparent “superior intellect,” it was rather because Light was a literal adult woman shoved in the body of an infant.
Regardless of the reason behind it, Sachiko was pleased. She liked to tote Light around to her mommy get-togethers and gush about her child’s achievements. The other parents smiled and nodded, most likely wishing her luck on a terrible two’s phase that never arose. Sachiko was once more pleased: Light was such an easy child.
Sayu, on the other hand?
“Honey, I can’t understand you,” Sachiko desperately tells a wailing Sayu seated in a high seat.
“I wan—” she blubbers, “I wan’ more milk!”
“There’s already enough milk in your cereal,” Sachiko says, pushing the bowl towards her.
Sayu flails her arms. “NO! I WANT MORE MILK!”
Sachiko shakes her head and casts her gaze at Light. She then checks the time and begins to fret. “Oh, goodness, I’m going to be late.”
She then throws on a coat and heads for the door. “There’s lunch in the fridge that can be heated up. Fujimoto-san should be here any minute.”
And then she’s out the door, gone without a glance backwards.
Light stands there for a moment, letting the sound of the locking door and the wailing toddler wash over her. And then she’s turning towards Sayu and climbing up onto the table to get a better look at her high seat.
“You want more milk?” she asks.
Sayu nods her little red face up and down. “Yu-huh! Milk p’eas!”
Light glanced down at the bowl of dissolving mush pretending to be cereal. “In your cereal?”
“NO!” Sayu bellowed, “MILK! WAN’ MORE MILK!”
“Got it.” Light grabbed the bowl and climbed off the table. She put the bowl on the counter, climbed it, and pulled a sippy cup out of the cupboard. Light tipped the bowl into the sink and turned it on to let the water wash the mush away. She then climbed back to the floor, opened up the refrigerator, hefted the gallon of milk out of the door, and poured a cup for her sister.
“More milk,” Light said, screwing on the top and standing on her tiptoes to place it on Sayu’s high chair. “Drink up.”
She sniffled and pulled the cup towards her. After a few minutes, she set it back down and said, “T’ank you.”
“You’re welcome,” Light answered back, “Do you want to play now?”
Sayu nodded again. Light began the arduous task of safely pulling her out of the highchair and onto the floor. Her little sister darted off straight to the living room, with Light quick to follow. Just like she always did, Light pushed the coffee table out of the way, laid out a blanket on the rug, and dumped an old box of colorful blocks onto it. Sayu, just as she always did, cheered and began her cycle of building up some tower or other, and then knocking it down.
Before Light joined Sayu in her playtime, she hopped up on a chair, cleared the dishes from the table and into the sink, and swiped the envelope of cash Sachiko had left behind.
“¥6000 at ¥1500 an hour leaves me with four hours of babysitting,” Light thought, “Sachiko usually ‘leaves us with a sitter’ roughly twice a week. If I assume that rate is consistent, by the end of the year I’ll have ¥624,000 to my name. Assuming a conversion rate of ¥150 per $1, that’s…. $4160. Give or take.”
Light nodded to herself and raced up the stairs, shoving the envelope under her mattress like all the other envelopes over the past month.
Fujimoto-san, the retired widow who lived a few doors over, had originally been their babysitter until she had taken an unfortunate tumble that limited her mobility. She had sent over her grandson to babysit in her place, but once he entered college back in April, he had stopped showing up.
It was now July, and no matter how Light tried to explain it to her ‘parents,’ they still had yet to understand that she was the one looking after Sayu. Souichirou wasn’t around enough to see it, and the few times Light stayed up late enough to see him stumble home from work, he was too sleep-deprived to understand her words. And Sachiko? Don’t make her laugh: the woman was a master at misunderstanding her children. After half a dozen cooing sessions over Light being ‘such a caring big sister’ and ‘how she’ll be making a man very lucky in a few years,’ she could only assume it was intentional.
So, Light gritted her teeth and babysat. She had the phone numbers of poison control and her favorite takeout places memorized, and she didn’t feel an ounce of guilt about pocketing the money Sachiko left on the table. After all, it was for the babysitter, and that could only mean Light.
“Nee-chan, nee-chan, look!” Sayu called once she turned the corner from the stairs and back into the two-year-old’s line of sight. “Raaaahhhh!” She destroyed the block tower with a well-placed kick before flopping onto her back and giggling like mad.
“Very cool, Sayu!” Light cheered, “Let’s see if we can’t build an even bigger one!”
Sayu cheered back and scrambled to do just that. Light looked on, smile indulgent.
“Well,” she thought, “At least the kid’s cute, even if the parents are trash. Still wish I wasn’t the one stuck babysitting.”
*****
About a year later, six-year-old Light takes the next big step in her overarching plan to not become the megalomaniac, god-complex-riddled serial killer known as Kira. She figured she already had a pretty good start there, seeing as she didn’t believe in the death penalty in any way, shape, or form, but Light did have another ace up her sleeve she was eager to play.
Namely, Light had her eyes on international colleges. If she could remove herself from the equation entirely, it wouldn’t guarantee getting L’s one-track mind off her ass, but it’d at least be a start. But an exit strategy like that came with a huge fucking price tag. If Light even wanted a chance, she’d have to start saving now.
So when her elementary school sends the Grade 1 kids home with permission slips saying that everyone will be taking a field trip to the local bank and setting up their very own bank account, Light jumps at the chance.
Sachiko smiles indulgently, proud of her prodigy daughter for taking an interest in such ‘grown-up’ things. She signs the slip and adds in a pretty ¥5000 to cover the minimum amount needed to set up the account plus a ‘little extra treat for my sweet Light-chan.’ Light shamelessly asks a sleepless Souichirou for ¥5000 more, and then adds her babysitting money to the pot.
The next day is Tuesday, May 19th, 1992. The pack of grade-school children tours a fairly impressive bank, and then one by one are escorted back to meet with a financial advisor to help set up their bank accounts. When Yagami Light is called back for her turn, the advisor doesn’t quite know what to do with the six-year-old who sets one signed permission slip and ¥634,000 on her desk. Light, though, scrounged up every ounce of past knowledge, logged hours of research on the library computers, and came in with a game plan.
It was 1992. Japan was at the very beginning of the first Lost Decade, a period of financial stagnation for the country as a whole. The US dollar was weak, and the Japanese yen was even weaker. The Information Age was soon to be upon them, requiring all of the computer chips and circuit boards that went along with it. Gold was soon to become a very, very lucrative resource, both in industry and in economics. One share of Royal Gold Inc. was roughly $0.12, and $1.00 equal to roughly ¥130. So at roughly 8 shares/¥130, Light asked her new investing account manager to get in touch with Interactive Brokers to buy 4000 shares for ¥520,000, leaving around ¥114,000 in her account to collect interest.
Light’s financial advisor agrees and gently asks which she would prefer to be placed on her account: a compound interest rate of 6.50%, or a simple interest rate of 8.50%. Light smiles and tells her that a compound interest rate was just fine with her, thank you, and that she should please not sell any shares of Royal Gold Inc. until she said so.
That’s the last Light sees of the bank for quite some time. It won’t be until February 23rd, 1996—five days before her tenth birthday—that Light will get a chance to return and manage her finances again. By then, she had saved a massive ¥2,352,000 from the four years of babysitting, and another ¥50,000 or so from birthday, Christmas, and New Year's gifts. She sells all 4000 stock for about $8.12 a piece, netting her $32,000. Unfortunately, the exchange rate hadn’t swung in her favor: $1.00 was now about ¥105. Still, that was a net gain of ~¥3,360,000. Combine that with her deposit and the new sum from the compound interest, and Yagami Light had a grand total of ¥5,931,642.59 in her bank account.
“A little more than $50,000. Not bad,” she thought, “But not quite good enough.”
She asks her account manager to buy ¥5,250,000 worth of Microsoft stock, leaving ¥681,642.59 in the account to collect interest. At the current going price of $3.96 per share, that’s about 12,626 shares to Light’s name. She won’t be able to sell those shares for what Light knows is the height of their value, but she’s willing to sit on the investment and wait it out regardless. Only a fool, after all, would turn away a known thing.
And so Yagami Light, a few days shy of ten years, rushes back home before Sachiko or Souichirou can realize she’s gone. Sayu, of course, had already been sworn to secrecy and bribed with the first piece of choice from Light’s birthday cake. It wouldn’t do for her younger sister to feel neglected.
*****
Light comes home from school on February 28th, 1996, to a dark, empty house.
That in and of itself isn’t unusual. Were this any other day, she wouldn’t bat an eye at Sachiko and Souichirou not being there to welcome their two daughters home from school. But this wasn’t a normal day.
It was Light’s birthday.
And yeah, sure, she had technically already celebrated her real tenth birthday a lifetime ago, but birthdays were the one day a year that the Yagamis actually acted like parents. Sachiko would organize a little party with her friends and their kids, and Souichirou would take the day off from work and exchange more than two sleep-deprived words with his daughters. Light was looking forward to having one day to herself. One day of not being the de facto caretaker and parent to Sayu. One day of being the kid she should’ve been.
Sayu must’ve picked up on her dismay and annoyance because she poked her and said, “Mom and Dad must be planning a surprise party for you!” trying to lighten the mood.
“Sure,” Light allowed, still suspicious, “Maybe I’ll get that board game from the new commercial.”
They watch TV for a bit. As the clock ticks down with still no parents in sight, Light purses her lip and makes her and Sayu some dinner. Sayu insists on singing Happy Birthday to her over their steamed veggies. Light picks up the dishes and then settles in to do her homework.
Finally, just past eight o’clock, Sachiko and Souichirou stumble in. They’re giggling like school kids and swaying a bit on their feet.
“What are you two still doing up?” Sachiko asks once she sees them sitting at the table.
“Waiting for you to get home,” Light answered honestly.
“Aw, that’s sweet, but don’t worry about your father and I,” Sachiko said, “We were just enjoying date night!”
Light blinked slowly, letting that information soak in. “Date night?”
“I apparently requested today off weeks ago, but I couldn’t remember why. So your mom and I just took the day to enjoy each other’s company,” Souichirou explained patiently. There wasn’t a single look of recognition in his eye: not a single suspicion that today may have held any significance beyond a random day off of work. “You’re much too young to be thinking about romance right now, but make sure your future husband always take time every once in a while to show you how much he cares. It’s important to keep the romance alive.”
Light couldn’t believe what she was hearing. She had to fight to keep her expression completely blank as she tried to process. Sayu was huffing and puffing in anger, her face beginning to turn a scarlet red. Both of these reactions went uncommented on as their parents stumbled up the stairs.
“Well, don’t stay up too late! You’ve got school in the morning.” Sachiko called to them. Souichirou whispered something in her ear that had her giggling. They raced up the rest of the steps, half-drunk on liquor, half-drunk on love.
The second they heard the door to their bedroom click shut, Sayu slammed her hands on the table. “It’s not fair!” she cried, “It’s your birthday and they didn’t get you a present, or, or a party, or a cake, or anything! We waited for forever and they didn’t even remember!”
“It’s okay, Sayu,” Light said calmly, “It’s okay. People forget things.”
“Yeah, things! Not birthdays! Not when it’s people you love!” she said with conviction, “Do they not—don’t Mom and Dad love you?”
“That’s….I….” for whatever reason, it was this earnest question from her sister rather than her new parents’ mistake that burst the dam of tears. “I’m sure they—that they lo-love us in their ow-own w-way, but,” Light gasped around sobs, “But I don’t—I, I don’t think they’re good parents. Not….not the way parents sh-should be.”
Light wiped at her eyes and sniffled. Sayu flung herself out of her seat and into her arms.
“‘m sorry you had a bad birthday,” she whimpered as the two sisters clung to each other.
“Hey, it wasn’t all, all bad, right? I got to spend it with you,” Light sniffled, forcing herself to crack a smile for the other girl.
Sayu nodded seriously. “Yeah. Birthdays are for sisters, not for fake parents who don’t care.”
“Birthdays are for sisters,” Light agreed. As she held the other girl tight, she felt her heart break and reshape itself, and knew she had come to a life-changing realization.
“I actually love this kid,” Light thought, “Not as a replacement for my old family, but just as she is. Just as Sayu.” And then a split second later, “Fuck, I need to change my exit strategy. She’ll be what, fourteen when canon comes around to fuck us over? Doesn’t she get kidnapped by the mafia and traumatized bad enough to go catatonic? Fuck. Fuck!”
Light had seven years to rewrite the universe. Seven years to plan and prepare and get her and her sister the hell out of dodge.
“Fuck you, L. Fuck you, Kira,” Light thinks, “I’m not letting anyone or anything ruin her, not even me.”