The multiverse is a theoretical collection of either infinite or finite possible universes, encompassing everything that exists or could exist: all of space, time, matter, energy, and the physical laws and constants that describe them.
It is the realm of the Imaginary Tree—the laws governing cosmic operation, the secrets of the cycle of life, and the origin of all essence and truth.
It is the eternal moment, the genesis of the end, the birthplace of all truths and principles.
Rooted in the Quantum Sea, these forces together form the world of Honkai, locked in endless competition.
Time flows along the trunk of the Imaginary Tree.
Like the canopy of a great tree, it branches out into countless worlds, each limb giving rise to a different universe.
Just as a lush, towering tree has countless branches, when these divergences happen at specific coincidental moments, they can give birth to remarkably similar worlds.
Such is the case now with Honkai Gakuen 2 and Honkai Impact 3.
Though the odds of such possibilities are as minuscule as dust, within the infinite scope of the multiverse, as long as the probability isn't zero, it will happen.
In these seemingly familiar yet different worlds, there can exist people or objects completely identical to those we know.
Not just in appearance, but in higher-dimensional traits such as essence, fate, and soul. Everything about them could be a mirror image.
These are known as "Other Selves"—alternate-dimension counterparts.
From a rational standpoint, such counterparts might be called brothers or sisters.
But in truth, the bond between them often surpasses that of blood relatives.
What others might feel about such a phenomenon is unknown—but if Nagami were to meet his own counterpart from another dimension, his response would depend on the other's personality and mindset.
He might treat them like a stranger… or go as far as to consider them as his actual self.
"That really is something to think about… If I treat this world's Kiana as a sister, then would K423 be my... aunt? Or sister?"
The heiress Kiana tilted her head, her twin braids swaying along with the motion.
She thought for a moment but couldn't come to a solid conclusion.
"Well, purely from a biological standpoint, you and your counterpart have identical genes. So, technically, calling you 'mom' wouldn't be too much of a stretch~"
With a soft laugh, C.C. raised her teacup and glanced at Kiana, whose expression was caught somewhere between awkward and conflicted.
"Let's not go with 'mom'..."
Kiana smiled politely, albeit with slight embarrassment.
Even after learning that C.C. was, in fact also Nagami, she still tolerated his teasing more than most.
"Do you feel anything… about the 'you' in this world?"
C.C.'s tone was calm as he looked directly into the eyes of the silver-haired girl before her.
Her face, usually soft and relaxed, now held a rare seriousness.
In her golden irises, something stirred—like ripples across still water.
"There does seem to be… something."
Kiana nodded subtly and turned her head, gazing off into a specific part of the empty space in front of her.
She lifted a delicate finger and pointed northward, her expression reflective.
"It's a strange feeling… I can't really explain it, but I think the Kiana of this world is in that direction."
So the connection between counterparts across dimensions does exist!
Narrowing her golden eyes slightly, C.C. recalled scanning through what must've been several terabytes' worth of the chat group's handbook.
Her theories about alternate counterparts were being proven right before her eyes.
And now… if Kiana could sense the exact direction, then locating the real Kiana was essentially a done deal.
Grabbing the tablet from the sofa, C.C. opened the map and aligned it with Kiana's pointing direction.
Her slender fingers slid across the screen, drawing a red line that cut straight through Nagazora City.
She kept zooming out, shrinking the map until it resembled an unfolded globe.
Extending the line, it now spanned across the entire northern hemisphere. After saving the map and locking the screen, she stood up.
In front of Kiana's glowing eyes, C.C. shed her loungewear and changed into her favorite sleek black dress.
Picking up the car keys, she casually reached out and held the girl's soft hand, her expression gentle and friendly—like a big sister or a close friend.
"Let's go."
"Eh? Go where?"
The warmth of C.C.'s hand surprised Kiana, and she glanced over at the effortlessly cool green-haired figure.
"We're going to locate this world's Kiana. And once we're strong enough, we'll try to rescue her from Schicksal."
"You don't want to see her subjected to those inhumane experiments, do you?"
Calling them inhumane might have been a bit of an exaggeration.
After all, as a one-of-a-kind test subject bearing the bloodlines of both the Kaslana and Schariac families, the researchers likely wouldn't risk her in overly dangerous tests.
"Yeah!" Kiana didn't hesitate for a second.
Even though Nagami hadn't uploaded detailed intel on this world's real Kiana to the chat group, she was smart enough to infer from Schicksal's known data that her alternate self's situation was likely… very bad.
No one could sit back and watch their alternate self suffer without doing something, right?
Even if that person technically had nothing to do with her, Kiana's strong sense of justice would never let her turn a blind eye.
"But… how exactly are we supposed to find her?"
Sitting in the passenger seat, Kiana buckled her seatbelt and turned her head toward C.C., asking with a hint of concern.
The car's jet-like exhaust flared with a flash of cyan-blue light as the engine roared to life.
In the dim underground parking garage, the sports car left behind a dazzling blue streak, its powerful engine growling as it tore off into the night and merged onto the open road.
"Uh… what? Did I say something wrong?"
Her twin braids danced in the air like flowing streams.
Kiana glanced over and noticed the odd look on C.C.'s face, as if wondering why she would ask such an obvious question.
"It's simple logic: two non-parallel lines are guaranteed to intersect at some point."
C.C. couldn't help but wonder if Kiana's brain had been infected by a honkai beast—this was basic middle-school geometry.
"Oh… right."
Kiana scratched her cheek sheepishly, realizing she had asked a pretty dumb question.
But it wasn't entirely her fault—C.C.'s presence was just too distracting.
They didn't need a specific destination—just somewhere far enough from C.C.'s home to make a proper reading.
So C.C. took the car down the least-traveled roads, and with a single stomp on the gas pedal, the vehicle shot forward like an arrow released from a bow, blurring into a phantom of speed.
She drove dozens of kilometers in a direction that veered about 90 degrees away from where Kiana had pointed earlier.
Once she figured they'd gone far enough, C.C. finally pulled over.
The sky overhead was an endless wash of clear blue.
Fluffy white clouds drifted lazily on the wind. A flock of birds rested on the fresh green grass.
The trees whispered softly as the breeze rustled through their leaves—it was a peaceful scene.
A park neither of them recognized.
"Can you still sense where your alternate self is?"
Without getting out of the car, C.C. reached into the back seat and grabbed the tablet again, pulling up the map they'd marked earlier.
"Hmm…"
Kiana took a deep breath, calming herself.
With her eyes closed, her long lashes trembled faintly before she slowly opened them again. "That direction!"
C.C. followed the direction Kiana was pointing, then turned back to the map.
On the full-scale layout, she drew another red line in that direction. Then she zoomed out.
And out again. She extended the new line until it eventually intersected with the first one.
'Found it.'
"Let me see~" Kiana naturally wrapped an arm around C.C.'s shoulders, beaming brightly as she leaned in close.
"Europe… right here… This should be one of Schicksal's top-secret research facilities. I remember catching a glimpse of it on Mom's terminal once."
In the current timeline of Honkai Gakuen 2, Kiana mother hadn't kicked the bucket yet and was still the most powerful Valkyrie in Schicksal.
And aside from Otto's usual backdoor schemes, there wasn't much that Schicksal actually kept secret from Cecilia.