I'm not happy how this turned out. It definitely needs some polishing. But meh. I'm re obsessed with DN now. And since I always disliked how painfully underused Sachiko and Sayu were on DN, I decided to post this.
Not a native English speaker, so feel free to point out any mistakes.
Sachiko choose Light's name. When he was born, he cried a lot, and the doctor congratulated her for having "a strong boy with healthy lungs"
Then he left her alone with her first born. Soichiro was sleeping on the waiting room after a difficult 7-hours birth and having to work non-stop on the police station the previous nights. The doctor offered her to wake him up but she refused, Soichiro was tired, and Light wasn't going nowhere. His boy was going to be here when he woke up.
The boy was beautiful. And not in the way that all mothers say about their kids. Not, he was truly beautiful, specially for a newborn. He had rosy cheeks, dark brown hair on his tiny head, slim eyes of a soft blue, that would darken over time. He looked at her and Sachiko feel his heat bursting with love. Not even Soichiro had make her felt that way before. She embraced him, wishing for all evil to disappear so nothing would ever taint her innocent boy. Her Light.
So he named him like that. He was going to be a spot of bright light in this rotten, dark world.
When Light was three years old, she discovered her son was a genius.
She was busy preparing dinner, when she saw Light in the breakfast table, pen and paper on hand.
"What are you doing honey?.
"Writing"
She thought that he was "writing" like all kids his age said when drawing random lines. So he was surprised when she saw Light writing his family' name 夜神 in big, shaky lines. Then he stopped.
"What it is, honey"
"I don't know how to write the rest."
"Here, let me help you."
She wrote 月. Her elegant calligraphy contrasted heavily with the shaky scribbles of Light's chubby fingers. Then he frowned. The serious expression looked out of place in his childish face.
"That not right" he was still frowning. It was cute.
"Mm?"
"Here says Moon. My name is not Moon. It's Light"
She was even more surprised. She thought that he was just repeating his name from memory, but if he knew that the kanji of his name was Moon, she realized that...
"Light, what does it says here?" She asked pointing to a cereal box in the kitchen counter
When Ligh read it, she realized that her son didn't only knew how to write his own name, but he learned to read autodidactically! She wrapped him on his arms, explaining his kanji to him, while thinking in how blessed she was to have a son as bright as him.
Instead of cooking dinner; that night they decided to go a fancy restaurant to celebrate.
Before Sayu was born, she was worried.
She loved Light so much, that she wasn't sure she could love Sayu the same way she loved Light. She didn't want to make differences between her children.
But Sayu was born and she felt her heart burst in love again.
But she still wondered if Sayu was going to be as bright as her brother.
Both her and Soichiro tried to never make differences between their children, but sometimes they slipped.
He wouldn't never admit it , but she knew that Soichiro favored Sayu over Light.
It's not like Soichiro didn't love Light. Hell no. He loved him and would do anything for him. But Light was so independent. He never needed help with his homework, he always keep his room in perfect order, he was always polite. He was the closest thing to a perfectly behaved son.
In contrast, Sayu was painfully normal. She always whined about how difficult school was, her room was a mess of clothes, and she was sometimes rude like most kids are. And she wasn't only a little girl in need of protection of his big, powerful dad, but she was normal too. And she knew that Soichiro will never admit this, but Light's effortless perfection since such a early age scared him a little.
And that was okay, she thought. Because Light was her favorite, even if she never would admit it out loud either.
She realized her son was going to be a ladies' man when he was ten in St Valentine's Day
For that day the school was holding a bake sale in Yoyoshi Park. Sachiko had prepared peanut butter cookies and a sponge cake, and to her satifaction her recipes seemed to be the most popular out there.
Light was silently seated on her left, while Sayu was crying her eyes out, because she wanted to go home.
Every table in the sale had a small bag, where the parents leave the card of their child there. Sachiko was surprised when she saw how many parents where coming to her table, and not just to get cookies and cake.
By the end of the day, Sachiko counted 23 love letters and many candies for Light. He got the most letters and candies on the class. Miss Park, the neighbor next door, Sachiko's friend and owner of her favorite flowershop, laughed seeing this, and ruffled Light's hair, telling him how he was going to be "a hit with the ladies" when he was older. Light smiled politely at the woman, although Sachiko doubted he actually knew what she was talking about.
However, the real winner that day was Sayu. Light never cared much about sweets, so all of them ended in Sayu's tummy.
She wasn't surprised when her son and husband disappeared for months in the cusp of Kira's investigation, led by the mysterious detective L.
Sachiko was just a simple housewife. She liked that life. But she graduated top of her class in highschool, and she also graduated Summa Cum Laude* with honors from college. She wasn't a simpleton.
She remembered how Light came to life again when Kira appeared. How the mask of indifference and boredom that had occupied his face for so long was left behind, leaving space for the vivacious sharpness that had disappeared for his eyes years before.
Kira, who wanted to made a safe world, just like her boy always wanted.
She once went to Light's room for laundry, and she looked to a piece of paper in the door, that wasn't there previously, placed in such an obvious way, as he wanted people to look at it. Or the even more obvious key on his desk. No one who really wanted to keep something secret as a diary would leave the key right there...
Light was more more alive than he had been on years, but he was also more secretive than ever.
Misa Amane was another factor. She could notice that Light didn't really liked her, despite being a beautiful woman who many men would kill to have in their beds. Why he was with her then? She also came into their lives roughly by the same time the Second Kira appeared...
All those facts danced on her head, and instead of doing something, she just ignored them, pretending that everything was okay.
By the time Matsuda Touta came to her home, in an apologetic manner, telling how Light had been another of Kira's victims, it was too late. She almost laughed at his pitiful attempt to create a merciful lie. She would have laughed, if her heart wasn't already breaking on pieces. First her Soichiro, now her Light.
She may not be a simpleton, but sometimes it was easier to pretend to be one.
That, and she was coward too. She never did anything.
All because she loved her son too much.
*I kind of like the idea that Light may have gotten part of his intelligence for his mother. Hell, according to some studies, people may inherit their intelligence for their mothers.