Between Subaru Natsuki and Emilia and Beatrice and Puck as siblings.
The scent of old parchment and ink lingered heavily as the light from the setting sun spilled through the windows of the vast library, casting long shadows across the countless shelves. It was here, amidst the silence of the forgotten and the whispers of the past, that Subaru Natsuki's fingertips grazed the spine of an unfamiliar leather-bound tome.
"What's this?" Subaru murmured to himself, the dust tickling his nose as he withdrew the book. The ancient writings etched into its cover seemed to dance before his eyes, glowing faintly with an otherworldly shimmer. The quiet hum of magic was unmistakable, even to an untrained ear like his.
Subaru cracked open the tome, and the pages fanned out, restless. Each page fluttered as if breathing, the words rearranging themselves with every blink, and they spoke of a realm parallel to his own, one which set his heart pounding with both excitement and unease.
"Beatrice?" Subaru called out, hoping to hear her sharp retort or at least her disinterested huff, but there was only silence. He called again, louder this time, the concern rising in his voice.
Only moments later, the girl in question drifted into view from between the high stacks of books, her small frame barely casting a shadow. Beatrice's gaze was cool and inquisitive, her ever-present air of annoyance seemingly on pause. "What is it that has you calling out so desperately, I suppose?" she inquired, fixing him with a look that demanded a proper explanation.
Subaru held out the tome for her to see. "Look at this, Beako. This book... it's talking about a different world. A place where you and I... we're not just friends or... um, contract partners," he stuttered with a growing sense of wonder. "We're... siblings."
A ripple of shock flashed across Beatrice's face before she quickly masked it with her standard indifferent facade. Yet, there was no denying the crackle in the air, the subtle shift in how she now regarded Subaru. "Siblings, you say?" she pondered the word, tasting it, rolling it on her tongue as if she'd stumbled upon a new spell. "That's quite a bold claim. Show me this farce, I suppose."
Together, they pored over the aged pages, tracing lines of text that spoke of a shared history, of a bond deeper than time itself. It was a ludicrous thought, but the unsettling truth of the magic before them refused to be denied. And as the reality of this other world began to sink in, a strange warmth bubbled between them, an ember of kinship that neither had expected, nor knew they yearned for.
A soft, knowing chuckle interrupted their study. It was a sound both familiar and comforting, and they turned to find Puck floating lazily in the air, his feline tail swishing with mirth. "Well, this is an interesting development," Puck said, his eyes gleaming with a mixture of pride and amusement. "Never thought I'd see the day when you two became siblings."
Subaru rubbed the back of his neck, a sheepish smile taking form. "It's pretty weird, huh? But if it's in this book... and there's magic in it... then maybe there's some truth to it."
Beatrice closed the tome, her fingers lingering on the cover, reverent. "If it's true... then perhaps I've greatly misunderstood the nature of our connection all this time, I suppose," she said softly, something like regret—or was it hope?—flickering in her lilac eyes.
The library around them seemed to hold its breath, waiting, watching, as if the very walls themselves could sense the shift in the air. Like the turn of a page, everything had changed, the story of Subaru and Beatrice no longer just a tale of coincidence and necessity, but one of possibility and the whispers of a newly discovered fate.