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Nanako suddenly walked over to Lily and stood with her legs straddling the outside of Lily’s own, looking down at her from an angle that felt distinctly dangerous.

“Sister… you’re so beautiful.”

“Oh, come on. We’ve been sisters for so long already. Why are you suddenly saying something like that?”

“Why is it that we’re both girls, yet I’m so completely different from you?”

‘Isn’t it precisely because of those differences that we’re drawn to each other?’ Nanako wanted to say those words, but in the end, she held them back. Regardless of what Lily herself thought, that was how Nanako truly felt.

But… did Lily really feel the same? Thinking about it rationally, it was like this: every man in the world adored Lily, but would a woman like Lily fall in love with ugly men simply because they were so different from her? Of course not.

Naturally, Nanako knew Lily didn’t like men. It was only an analogy. Every one of her sisters adored great beauties. Yet great beauties only loved other great beauties. They would never fall for an ordinary little sister like her.

‘She could never fall in love with me…’

“Sniff…” A wave of bitterness welled up inside Nanako’s heart, and before she realized it, tears began to fall.

Lying on her stomach, Lily lifted her upper body slightly. Her heavy, snow-white breasts brushed softly against the floor through her clothing as she turned her head to look at Nanako. “Nanako, what’s wrong?”

“It’s nothing… Even if I told you, you wouldn’t understand.”

A trace of sorrow rose in Lily’s eyes. Nanako had shared hardships with her, had risked life and death for her countless times. Lily wanted to use whatever strength she had to help Nanako regain her spirits and smile again.

“Nanako, didn’t we say we were going to uncover the secrets of this world? Have you thought of any good ideas?” Lily asked teasingly, her voice carrying an unexpectedly alluring softness.

“What ideas does Sister have?” Nanako asked in return.

“Hmph.” Lily pouted slightly. “How would I have any ideas? I’m the mistress, and you’re the maid, aren’t you? This is an upside-down world, after all.”

Having gone that far, Lily found herself too embarrassed to continue. She lowered her head, lay back down on her stomach, and closed her eyes. “You take your time thinking, little sister. I am going to nap for a while.”

“……”

Silence settled over the dim room. After a short while, Nanako finally spoke. “Sis… the collar.”

“Huh?” Lily’s delicate body trembled.

“Do you have one, Sis? A collar?”

“I… I do, but why are you asking all of a sudden?” Lily had never returned all the treasures she had confiscated from Furaku. Although she had returned some while they were at the celestial maiden stronghold in Takamagahara, she had still been testing her, and before long they had parted ways.

“Did you already forget what the innkeeper downstairs said? The rules of this world.” Standing where she was, Nanako asked calmly, though her gaze still wavered slightly as her breathing gradually steadied.

“Huh? W-What…? I… I don’t really remember,” Lily replied nervously.

‘No way… Nanako actually wants that?’

She certainly wanted to investigate the mysteries of this world with Nanako, but… this was Nanako, her precious little sister. How could she possibly give her something like that? Besides, what did she even intend to do with it?

Deep down, Lily already knew the answer.

“Sis, now you’re the one refusing to cooperate. Weren’t you just asking me if I had any ideas? Well, my idea is for Sister to say it herself. Why don’t you think carefully about what the innkeeper said? If you don’t want to investigate the secrets of this world anymore, then forget it. We could just stay here forever.”

“Nanako, don’t say such nonsense. How could we possibly stay here forever? We have to leave this place as quickly as possible. For that, we have to try every possibility that’s necessary,” Lily said.

“So…?”

Lily propped herself up on her elbows, easing some of the pressure crushing her chest. Her breathing grew uneven as heat spread across her face. After all, the turbulent emotions she had accumulated throughout this journey had yet to be properly calmed.

‘This Nanako… she’s making her mature older sister say something like this on purpose. Is she deliberately trying to embarrass me?’ Lily complained inwardly.

Still, she sighed helplessly, brushed aside a lock of hair from her forehead, and said, “I am determined to uncover the mysteries of this world no matter what… Th-that… that innkeeper said… that… in this world… noble ladies are supposed to…”

“Ahhh!” Lily buried her face in her folded arms in frustration. “I am too embarrassed to say it!”

“So that’s how it is… You really think Nanako can’t face hardships together with you. You don’t trust me after all…”

“Don’t say that. I do trust you.” Lily looked at Nanako with a helpless, almost plaintive gaze. “Fine… I’ll say it. I’ll say it, all right? The innkeeper simply said that the young ladies of this world all wear collars, and their maids lead them around with leashes. That’s all. What’s the big deal?”

Although she forced herself to sound casual, the rise and fall of her chest only became more intense.

“Then, shouldn’t we follow the customs of this world as well? Otherwise, how are we supposed to uncover its secrets?” Nanako asked.

“Huh?” Lily turned over, one hand instinctively clutching her lapel while the other hurriedly pulled down the hem of her skirt to cover the pale expanse of thigh exposed by the movement.

“N-Nanako… y-you’re joking… aren’t you?”

“Why would I be joking? That’s simply how young ladies are in this world. Besides, our mistress-and-maid relationship isn’t pretend. You really are my young lady. Shouldn’t we follow the rules of this world?”

“Absolutely not!” Lily frowned with a trace of anger, speaking with righteous conviction. “That only proves how bizarre this world is! We came from a normal world. I’m your older sister, and you’re my younger sister. Since when would an older sister let her little sister… l-lead her around with a collar?”

“Hmph. So because millions of demons desire you, covet you, and wish they could… do this or that with you…” Nanako paused before continuing, “…that makes your world normal? Is that really the kind of world you like, Sister? Thinking like that deserves punishment.”

“T-That’s not what I meant… It’s just…”

“Just what? If it were Sister Shimizu standing here instead, what would happen? Or Sister Uesugi? Would it be different then? Does that mean your little sister can’t be trusted to explore this world’s mysteries with you? Deep down, Nanako doesn’t even have a place in your heart, does she?”

As she spoke, Nanako began sobbing once more. “Waaah… For you, Sister… for your sake… I’ve already stopped caring about anything of my own. If you don’t like me… then my existence… has already lost its meaning…”

Lily’s entire body shuddered. That day, Nanako had leapt from the cliff without a moment’s hesitation for her sake. Who else in this world could possibly possess feelings for her that ran any deeper?

For her sake, Nanako had merged completely with Kagura, casting aside her own existence. She had remained within the mirror all that time, training in silence, willing to endure years without seeing her sister if it meant that one day she could be of use to Lily.

And had Lily ever truly cared for her in return?

Why? Why should she cling so stubbornly to her own feelings when her little sister had devoted herself so completely, so selflessly? Why was she the only one allowed to act according to her own feelings? Were all of her other sisters simply supposed to wait in silence?

True, Lily had never wanted to be treated that way. She disliked it. She truly, truly disliked it. But… If Nanako wanted it… Then she would give her that chance. Even if it embarrassed her. Even if she was unwilling. If it made her little sister happy, fulfilled, and feel cherished… Then what did it matter?

It was her responsibility to bring happiness to her older and younger sisters alike. Love could never be forced. But this was not ordinary love. This was devotion. This was the profound bond shared between sisters.

She ought to be more broad-minded. She ought to give more of herself. If this was what her little sister wished… Then so be it.

Exhaling softly, her breath fragrant as an orchid’s, Lily let out a tranquil sigh. She gazed at Nanako with tender affection before smiling in quiet relief. There was a newfound serenity in her eyes, as though her heart had become vast enough to embrace every grievance and longing carried by the petite girl before her.

“Nanako… I’m sorry. Big Sister was overthinking things. We only wanted to investigate the mysteries of this world, right? Your intentions were sincere. I shouldn’t have doubted you. Since this is what you want… then… let’s do it.”

“Huh? Sister…?”

Lily smiled with the composure of an older sister. Her slender jade-like fingers traced a graceful crescent through the air before turning over gently. Resting upon her palm appeared an ancient black collar crafted from the hide of a mysterious beast, together with a luminous pearl.

“Sister, what’s this pearl for?”

“Hm? Even I don’t know.” Lily deliberately answered with feigned indifference. “You’ll have to figure that out yourself, little sister.”

A small puff of white breath escaped Nanako’s lips. “What a naughty big sister. It seems I’ll have to discipline you properly.”

“Huh?” A blush spread across Lily’s face as warmth rose within her chest. “Calling your big sister naughty… how rude.”

This time, however, Nanako ignored Lily’s complaint entirely. She picked up both the collar and the pearl. “Then, Sister… Nanako is going to put it on you now.”

Looking down at Lily, Nanako’s gaze gradually fell upon the magnificent valley between her breasts, where tiny crystalline droplets glistened.

‘Her snowy-white neck is about to be adorned by the pitch-black collar. If only it could bind Sister’s heart along with it, that would be even better.’

As for the pearl, how it was meant to be used… Nanako’s gaze fell upon Lily’s slightly parted cherry lips. With her head lowered, Lily’s lips remained faintly open as she breathed in soft, unsteady gasps.

That night, it was Nanako, the younger sister, who held complete control over the situation.

As for Lily… She was merely a disobedient older sister who had made a mistake and quietly accepted her little sister’s punishment.

***

Only deep into the night did their exploration finally come to an end.

Nanako detached the leather leash from the collar and carefully put it away. She then wrapped the pearl in a silk handkerchief before storing it as well. A faint red mark still lingered upon Lily’s long, fair neck, making her look all the more pitiful.

As Lily looked at Nanako, although she had no desire to recall what had just transpired, she nevertheless felt a different kind of fulfillment.

Finding fulfillment in her little sister’s satisfaction seemed to deepen Lily’s understanding of the Heavenly Path of Charm. It was a deeper comprehension of the tenderness that came with being a woman.

Still, seeing Nanako put those items away left Lily with lingering trepidation. Weren’t those supposed to be returned to her…?

“I’m sorry, Sister,” Nanako said softly. “Did I… go a bit too far just now?”

Lily certainly thought she had. Far too far. Her little sister had been unbelievably naughty. Even if it had all been for the sake of investigating the mysteries of this world, who would discipline their older sister like that?

Yet Lily kept those thoughts to herself. Even when one suffered, it was better not to speak of it. Such was the grace and restraint befitting the peerless beauty of the Three Realms.

Instead, Lily gently opened her arms. Kneeling upright, she drew the petite Nanako into a warm embrace and whispered into her ear, “As long as my little sister is happy… that’s enough.”

“Sister…” A warmth spread through Nanako’s heart. “But Nanako cares even more about how you feel. More than anything, Nanako wanted to make you happy.”

“All right.” Lily smiled, both relieved and bashful, and whispered back into her ear,

“Then, little sister… you did.” As she spoke those words, Lily’s eyes were hazy and ethereal, impossible to fathom. Whether they reflected her true feelings… Or were merely an illusion… No one could tell.