"Here's every isekai I own that has a girl the protagonist knows transported to the same world." Bill Brock and Rachel were in the library—which all of the Brocks called the Lab—and he patted a stack of manga volumes. "Now, if I remember correctly you helped Xavier break the harem back in your sophomore year, right? Good, that means your back story is conducive to a romantic relationship, so we can pretty easily map out your likely trajectory if you get pulled into the isekai.
"The vast majority of these series present the main character as disadvantaged, even when they're actually absurdly overpowered. When they include a female foil, she usually contrasts the male MC's situation by being gifted or provided lots of support. Since you won't be showing up at the same time, barring time hijinks, that means that you'll likely be routed to a different geographic location somehow. Nothing we can do about that, of course; you'll have to play it by ear."
"What kind of support am I likely to receive?"
Bill shrugged. "It varies widely. Some common examples are receiving magical equipment, the backing of a powerful political power, innate martial or magical talents, the blessing of a god, absurdly good stats compared to your peers, or some combination. Hmm, I suppose there's an outside chance you might make some sort of contract with a powerful magical creature, but that's usually the protagonist's prerogative."
"And what's your advice if I get offered one or more of those things?"
"Take all the support you can get, but make sure you understand the strings attached first. The typical trajectory here is that the romantic interest gets embroiled in some shady business over her head and is eventually rescued by the protagonist. If you go along with the plot initially, that actually might make it easier to find him, because it will be very likely that he's working on behalf of some enemy country."
Accept all the support she was offered. Right. Except Bill's "outside chance" turned out to be an absurdly big, telepathic snake. Or dragon-thing. She still wasn't entirely sure.
"What exactly is it that you want?" asked Rachel, hands still pressed to the scale beneath her.
You have a yawning emptiness within, she thought to herself. God, that was not getting any less creepy with repetition. You must consume nima in great quantities, or die. I wish to fill that hole.
"What on earth does that mean?"
Consume me. Let me fill that hole within you, and you will be able to interact with the world like a native of this reality instead of being handicapped by your inability to touch nima.
Aside from the whole consumption thing, that didn't sound so bad. "Why would you want to be…consumed?"
I have grown too large. I had resigned myself to slowly becoming one with the earth until eighty six turns ago when I sensed the existence of an empty one like yourself. I came as fast as I could, but now opportunity strikes fresh.
"And if I don't accept?"
You may go your way. I will not harm you one way or the other.
Well, this certainly sounded like Bill's contract with a magical creature, but there had to be something she was overlooking. Aside from the fact that she didn't understand what this emptiness or nima or anything really was.
"If I do this, will I still be myself? Will I be able to go home?"
You ask good questions, little one. And yes, you will be yourself. You will simply have me as a…passenger, of sorts. Should you wish to tear the veil back open and pass through to your original reality, I am perhaps the only living being who might assist you. All I ask is that you spend some time in my world. I wish to taste freedom again.
"Freedom while trapped inside a tiny creature?"
Freedom to be something other than kami. Now, little one, I do not wish to stay on the surface if you are to reject my offer. What say you?
Rachel froze in indecision. All of her instincts were demanding that she refuse. She had no way to verify what the creature was telling her, no way to hold it to its promises, nothing but the shaky predictions of someone an entire reality away that whatever she discovered when she passed—through the veil, as the snake put it—would be there explicitly to grant her power.
On the other hand…she hadn't missed the fact that the snake was clearly looking for Xavier. Looking, and failing to find. Perhaps this powerup was originally intended for Xavier, but in typical Xavier fashion he intentionally avoided obvious examples of plot simply because he hated playing nice with the genre.
That actually made a scary amount of sense. And where Xavier always insisted on going his own way, Rachel had years and years of practice at accepting frightening new things simply because she had no good alternatives. What would making some sort of vaguely-defined contract with a giant, obviously magical snake monster do for her?
She'd just have to find out.
The words had barely left her mouth when a shudder passed through the snake that jolted Rachel almost off its back. Yeeeeeeeesssssss! she thought to herself, and then she felt a rush of something like heat or water or electrical shock and Rachel knew no more.
In the dark of her mind, Rachel dreamed snake dreams.
She was one of the last surviving recognizable descendants of the monstrous boas that stalked the jungles in ages past, and she was captured as a youngling by a tribe of the hominids who so recently had begun spreading far and wide. They fed her mammals of increasing size, and worshipped her as a god. She grew four times as long as a they were tall and spent the bulk of her time sunning herself in the enclosure where she was confined. When food grew scarce they provided offerings of nima and through trial and error she discovered she could metabolize it. In the lean times, when more hominids died than were born, she discovered she could sense the nima around her, even when it was not freely offered.
Then the ice descended, and her easy life ended. Fleeing after the warmth and nima she could sense just beyond the horizon, she came across a chain of mountains she had no hope of crossing and turned her attention to the smaller snakes that could still successfully kept themselves fed and needed less warmth to avoid falling into a stupor.
She was a viper, ambushing small mammals, biting them, and then following their trail as they fled until her poison did its work. The world was a thing of movement and heat, and she followed both through the nights.
She was a cobra, languidly sunning itself. Perhaps when she was hungry she would follow the nearby scent trail of another snake and eat it, but for now she was content to catch up on years' worth of missing heat. Sensing a tremor through the ground, she reared up, hood spread, growling in sudden alarm. The human that had been approaching her froze as her shadow snapped out across its body and slowly backed away.
She was a python, coiled high in the branches of a tree that shadowed the earth for a day's walk in any direction. With the rising temperatures and years of life she had grown to be many times the size of the humans who now flocked the earth, and while some once more worshipped her, none of them dared try to confine her.
The shelter of the tree was gone, and she was too large for any meal to truly satisfy. Seeking the nima that was her only viable source of sustenance, she passed down through the rock until she discovered the molten core of the world where she basked in luxurious warmth, emerging only occasionally when she sensed something that drew her interest. As the years passed, she was able to spend less and less time away from the raging nima in the world's core, driven back down through rock each time by ravenous hunger.
A tremor reached her, and in response to ancient instincts not her own, Rachel woke up.