In that vacant underground manor, where the only background noise is two girls' quiet breathing, it does not take much to break the silence. Discreet as they were, the soft footsteps in some vague distance were enough to raise the girl from her light sleep. Even as her slender frame slowly moved into an upright position, she glanced sideways towards the other end of the bed. In her just-awoken daze, she pondered over the empty sheets for a moment. Once it had passed, the information neatly registered. She mechanically slid off her own side of the bed, donning a nearby pair of slippers and grabbing a candle on her dresser.
Koishi, Koishi, just what are you up to now…
Finding a single girl in the dark, inside a massive palace, while half asleep, being guided by nothing but the sound of her footsteps, isn't normally an easy task. Even Satori herself wondered why she was going the way she was; it seemed as if her body moved without her guiding it in any particular direction. Perhaps she was too tired to care. She was not even sure of why she left bed to look for her sister. It wasn't as if Koishi was some child who would hurt herself horribly if left to her own devices, and she certainly hadn't deemed whatever she left bed to do dire enough to wake her sister for help. Still, groggy as she was, the protective instincts of an older sister easily dominated rationality. Onward Satori continued through the darkened halls.
At some point, the footsteps ceased. This should have made finding her sister near-impossible, yet Satori kept on moving. Even though the noise level had been minimal since she had awoken, now that her own steps were the only source of noise, the atmosphere seemed to become a shade more sinister. Satori had no fears as illogical as the dark – she'd seen far too many horrors far more real for that. It just seemed to her as if the air itself seemed to whisper to her: something bad is going to happen. She quietly dismissed the voices in her head as sleep-deprived hallucinations, but her legs started to move just a tiny bit more quickly.
It was the sound of glass cracking that properly wore her up. Not anything as violent as a vase crashing on the floor – it was a much more discreet sound, only noticeable because of the thunderous silence around it. If it had been such a sound, Satori would've likely been less worried, as it would've just turned out to be Koishi being clumsy in the dark. What Satori did hear – the sound so subtle it was clear Koishi was trying to not be heard – made her alert. Not quite worried, but alert enough to attempt to properly locate her sister.
When she heard the sound of glass slicing through air – an extremely subtle sound, one Satori likely wouldn't have heard if she hadn't just been startled to full awareness – made her properly worry. Even as she transitioned from a mechanical walk to a careless run, her head ran through a list of harmless explanations for the situation, each one less palatable than the last. The instinct which had led her before had all but evaporated, leaving her to glance into every doorway she passed. When she spied a light out of the corner of her eye, it was both a beacon of relief and a flare of tension all at once. She had found Koishi, but what else? Satori almost hesitated, but her body did not wait for her mind to reach conclusions, and sprang towards the light.
She wished she hadn't. She really wished she hadn't. She didn't want to see Koishi standing there, her eyes completely blank. She didn't want to see the glass shard clutched in her fingers. She didn't want to see the tiny pool of blood, formed on the ground from the droplets trailing from Koishi's third eye. And she most of all did not want to see Koishi's third eye, which looked so serene and so sinister with its eyelid closed, blood slowly flowing from the folds like tears.
And Satori did not want to feel the emptiness. The emotional emptiness – not her own, for her heart was far from empty at the moment. Koishi was empty. Satori could not hear a thing from her sister's heart, a very bizarre feeling for one who was accustomed to having the hearts of others laid bare to them. She quickly ran towards Koishi, for a moment afraid that the emptiness was borne of death. Yet, as she wrapped her arms around her sister and buried her face in her shoulder, she was certain she heard breathing, and certain she felt a heartbeat. Once again, it was a relief and yet only worried her more – her sister was alive, but in what state? The pair remained in that room, frozen like statues, illuminated only by a pair of candles: Koishi's, which had been carefully placed on a dresser, and Satori's, which she had let drop upon the sight of her sister. The silence was now drowned out only by Satori's sobs and heavy breathing.
It was Koishi who first spoke.
"I did it, Onee-chan." She said flatly, a perfect contrast to her sister's flaring emotions. "I closed my heart."
"Y-you what?" Satori managed to ask between her tears and gasped breaths.
"I closed my heart," she repeated in the same monotone. "Now people won't hate me. Now you won't have to worry about me."
Satori did not understand – did not want to understand. She merely held on to her sister, and so they passed that night in silence.