She and her brother were alike. They both had the same brown eyes, she reflected as she twisted a strand of her dark brunette hair that she had inherited from her mother (only a few shades darker than her brother's) behind her ear. They were both intelligent, although she was not nearly as smart as her brother was, and she would never dare compare her brain to his. She wasn't arrogant nor able to fool herself enough to even think that. But she was intelligent, and that's what most people didn't know about her, not even her parents. Light did though. Her grades never showed her capacity for fast thinking, because she wasn't smart academically, or streetwise, but in the ability to connect the dots. To draw conclusions. To see the greater picture on the puzzle. She was smart. She was also kind, and loved her older sibling very much.
That is why, when she suspected that her genius big brother might be the notorious serial killer, dubbed Kira by the inhabitants of Japan, she said nothing. When her friends at school asked her if she had any ideas about Kira, she simply smiled and laughed, asking rhetorically why she would know what Kira looked like, or who he might be. She would defend Kira at times, when he was being ridiculed at school, saying that the others didn't know who he was, or why he was doing what he was doing, and since he was only killing criminals, that meant he was good, right? Because deep down, she had connected all the pieces of the puzzle, and on that puzzle she saw her big brother's face. And someone on it, she saw her own. She knew she had the capacity to be Kira, if she had found the power her brother had.
It hadn't been difficult to connect the dots once the thought was in her head. He lived in the region of Japan that L had predicted was where Kira resided, but of course, a lot of people did. That was hardly evidence. He seemed to be spending most of his time in his bedroom, but he usually did so even before the killings, to study for classes or tests or entrance exams. He was boring in that way. Even if this hadn't been a habit before hand, he was a teenager. It was normal. But Light seemed more cautious afterward, as if he were closely guarding a secret. He became more distant. And then there was the paper in his door. She was observant, and she noticed it immediately one day as she was walking down the hall. A slip of white paper in his door. What on Earth would Light be doing that was so secretive that he needed to see if someone had been in his room. And then, there was the handle. Most people wouldn't notice it, but the handle was forcibly lowered a few centimeters, probably as a precaution.
She wanted so desperately to open the door, step inside his room, see what it was her older brother was hiding in there. It would be so easy, and she could replace the slip of paper and lower the handle just as it had been before. Her hand reached out for the metal handle, but she stopped. No, it was her brother's business…
She realized now, as she was being exchanged for the Death Note in Mello's grasp, that maybe it would have been better if she had opened the door. Or maybe if she had told someone. She thought this again, when she heard the news of her big brother's death, and cried in the arms of her mother.