I wrote a prequel story for Tranquility. If you don't know Tranquility, it can be found here: https://boards.guro.cx/3dcg/res/40140.html#44289 or on pixiv ( https://www.pixiv.net/en/artworks/104053953 I added a link to Russian translation in the description).

In case you missed it, Tranquility also has a sequel here: https://boards.guro.cx/3dcg/res/40140.html#45797 or on pixiv: https://www.pixiv.net/en/artworks/107327891

The following prequel can also be found on AO3:
- in Russian: https://archiveofourown.org/works/53939437
- in English: https://archiveofourown.org/works/53939617

Tranquility: Before Dawn
(Vocaloid, Kagamine Rin, Kagamine Len, casual consensual guro, hanging)

When Rin woke up, even before she opened her eyes, she could feel Len’s weight on the bed beside her, and so the first thing she did was to think about how she should wake him up today. It was their custom: whichever twin woke up first would wake the other one up in some fun and pleasant way. For example, Rin could wake Len up with a blowjob, or Len could piss right on Rin’s face. This time Rin thought — maybe wake her brother up with a tickle? But when she opened her eyes she saw that it was still dark and early to get up, especially today since today was a day off. So she should just try to go back to sleep, and then maybe even get her own special wake up from Len.

But before Rin closed her eyes again, she couldn’t help but marvel at her brother sleeping next to her. Len was sleeping so peacefully that it wasn’t even immediately obvious whether he was alive or dead. Rin involuntarily listened to his breathing… he was alive alright. Ha-ha, but of course he was! What was Rin even thinking? As if it could happen that she would wake up next to her brother and he would be dead and breathless. Rin imagined such a situation and almost giggled out loud, but held herself back so as not to wake Len up. The fact that they had always been and always would be together seemed to the twins an immutable law of nature, and the idea that one of them might suddenly be gone — and just like that, out of nothing: two of them fell asleep, and only one woke up next to the corpse of the other — this idea was so absurd that it caused neither fear nor sorrow, but only laughter. And the twins were known to be big fans of a good laugh.

Rin even wondered if she should on occasion give her brother a lethal dose of sleeping pills to wake up next to his corpse in the morning. Of course, she wasn’t thinking about making him drink the drug secretly or through deception. Rin knew that Len would be only too happy to kill himself if it would give his favorite sister a pleasant awakening. She knew this because she herself would gladly do the same for her beloved brother.

Wait, why doesn’t she do just that? After all, if she gave Len a sleeping pill, she’d know that she’d wake up next to his corpse in the morning, and it wouldn’t be the surprise she’d had so much fun imagining. But if it was Len who woke up next to her corpse… ah, — Rin almost shrieked with delight, — what a wonderful surprise that would be! It would be the best awakening she could give him. Rin couldn’t wait to get to it. And how could she hide her joyful anticipation from Len all day long, so as not to give herself away? And she would still need to get the right drug secretly from him, and all in all first properly study the question of what drug is the right one and how to do everything right. A thorough preparation might take even more than a day, increasing the risk that the surprise would be revealed early. For Rin didn’t come up with the pill idea because she was knowledgeable about it, but because she was thinking in the context of dying in the sleep.

Wait a minute… In fact, the point was to die while the other twin was sleeping, but the one dying didn’t at all need to be asleep. And if that’s the case, then by choosing another way of suicide Rin may not even need to wait for the next night, but do it right now, before Len wakes up! Yes, that would be best. Len wouldn’t see her eyes burning, giving away that she was up to something. For him it would happen that he had fallen asleep with a very much alive Rin, who herself had yet no idea of her impending suicide, and was genuinely anticipating the joy of meeting a new day with her beloved brother… and then he would wake up next to her already breathless corpse. Just like that, out of nowhere. It was exactly as Rin had imagined from the beginning, but in reverse: it wouldn’t be her who would get to laugh at the ridiculous death of her beloved brother, but he would get to laugh at hers. And to give such joy to Len was even more pleasant for Rin than to receive it herself.

The feeling of tenderness for her brother overflowed Rin’s heart, spilling over into her chest, all over her whole body, and she so wanted to kiss him. But she restrained herself. Not only for fear of waking him up, but also because it would be a farewell. And Rin wasn’t going to make farewells to Len. After all, the whole point was to leave just like that. Ha, “leave.” That word made Rin chuckle. After all, she wasn’t going to leave the confines of the room. Well, except to get some rope from the closet — Rin had decided to go for a hanging — and then she’ll be right back. And at the same time, when Len wakes up, she wouldn’t be here. She woudln’t be anywhere. She wouldn’t be at all. As a twin, Rin fundamentally couldn’t imagine how there can be no Len. And that means Len similarly couldn’t imagine the absence of Rin. So just how it would blow his mind when she is gone just like that! Without any preparations or goodbyes. She just was, and now she isn’t. Rin smiled smugly: what a great idea she came up with. Now she could be proud of herself for the rest of her life, ha-ha-ha!

Rin found a rope in the closet and tied a noose on it right there to keep the bedroom light off. When she returned, the first thing she did was to confirm that Len was still sleeping peacefully. She wondered what he was dreaming about? Ha-ha, certainly not the death of his beloved sister! Rin climbed onto the chair, put the noose around her neck, and tied the other end of the rope to a hook on the ceiling. She tugged — it seemed secure. It was so funny to organize her own death. Rin loved life, and she wanted to live, and she could live happily ever after with her beloved brother. But none of that mattered now, because she wasn’t at all killing herself to lose her life. She just wanted to make her brother feel good. And Rin’s own death wasn’t a sacrifice for that goal, it was a way to achieve it. Rin wasn’t thinking “it’s a shame I’m going to die, but so be it, if it’ll amuse Len”, instead she was thinking “it’s so great that I’m going to die, as it’ll amuse Len.” And she herself was amused by her thoughts going like that.

And it was with this positive attitude that Rin jumped off the chair. And immediately regretted it. She should have taken pills or cut her veins, as it turned out hanging was hurting like hell! The noose squeezed Rin’s neck so sharply that her eyes popped up, spattering tears. Panic rolled onto her in deafening waves, striving to overwhelm her, and only thoughts of her brother kept her from drowning in it.

Tears were blurring the picture, or maybe it was her eyes themselves that were already foggy, while involuntary spasms throughout her body made it hard to focus her gaze. Still, Rin stared at her beloved brother with all her strength. If only she could somehow reach out to him, if only she could let him know how she was suffering, dying, right here, within arm’s reach… She wanted to scream in pain, but with her throat constricted, only a muffled croak came out. Well at least it was something… would be better if there wasn’t even a croak. Rin was grateful to the rope clutching her throat for keeping her desperate pleas from waking Len too early. After all, he was sleeping so gently, so peacefully, unaware that at this very moment, right next to him, his beloved sister was suffering in dying agony. And what a beautiful contrast it was!

And soon it would be replaced by an even more beautiful contrast, mirrored like the twins themselves, when Len would wake up and first thing in the morning see a dead Rin. His heart would be filled with laughter, joy, delight, rupture and pure euphoria. Meanwhile, Rin would just hang there, swaying, in the noose, completely impartial to her brother’s bliss. But the fact that she wouldn’t get to share in Len’s fun was a source of joy rather than regret for Rin. After all, she knew that it would only amuse Len more. It would undoubtedly be the most pleasant awakening of his life….

…and how funny it was, that it was also the most agonizing “falling asleep” for Rin. Not only had she never before experienced such pain, but she couldn’t even imagine it. It seemed simply beyond human perception, her brain should have shut down from the shock by now, and yet even as consciousness began to slip away from her, Rin continued to vividly feel the severity of the agony. Her lungs were burning with carbon dioxide, and her heart was pounding desperately, losing all rhythm, her entire chest exploding with pain. Darkness swallowed the edges of her field of vision, but with a last willful effort, Rin was able to catch a glimpse of Len’s face. He was still enjoying a cozy bed and watching a sweet dream, where he was probably frolicking happily and carefree with his sister. And looking at him, Rin wanted to suffer even more, even worse, just to make the contrast with her peacefully sleeping and unsuspecting brother more beautiful. Even when he wakes up, he would only see her already dead and tranquil, and he would never be able to imagine the hell she had suffered. Hilarious! In the end it was great that she went for the hanging.

Every time it seemed that it couldn’t get any worse, Rin found out with genuine horror and no less genuine delight that they could. Every second… or minute… or hour…? Rin had lost her sense of time, and only knew for certain that each successive span of it was becoming more agonizing than the previous one. And the more desperate her agony became, the more pleasant it was to think of her brother’s peaceful sleep. Sleep, beloved brother, sleep the sweetest sleep while your precious sister dies slowly and painfully right under your very nose. And when you wake up, you’ll have the greatest gift in the world waiting for you. And it will be all yours and yours alone. Because that gift is that you will no longer have your inseparable sister to share it with. Can you even imagine that? You and I are twins, and there is no such thing as me not having you, or you not having me, it simply cannot be because it can never ever be. And yet be it will. Isn’t that magical?

Rin’s entire being was pierced by indescribable pain that clouded her consciousness, and she could no longer see her brother with her rolling eyes. But with her last thoughts, even if already very foggy ones, to just know that he was lying there quietly and peacefully, unaware of her agony, for Rin it was the most beautiful feeling in the world. It was so mesmerizing that Rin wished this moment would never end. Ah, but for her it would indeed never end! It was only for Len that tomorrow would come, filled with laughter and joy at her death. And Rin would forever remain here, in her endlessly growing agony next to the immutable tranquility of her sleeping brother. A finalized world of absolute bliss.