Ruby Rose, Her New Cock, and an Ero System (A LitRPG RWBY AU)

1. Rift

Ruby stared with wide silver eyes, coming to terms with what she was seeing.

The ovular incision into reality hovered with its bottom just brushing the grass. It was ten feet tall, about four wide, and zero thick—a plane with no volume. The glassy black material of its surface was darker than anything she'd seen. Blacker than pitch. So dark it seemed to suck nearby light in. Black and purple zaps darted here and there, crackling to her sixth sense, her highly-honed ability to identify aura and magic.

"Well," Yang finally said. "Would you look at that?"

"That's a Rift!"

"Sure is."

"In our backyard! A Rift opened in our backyard!"

"Captain Obvious to the rescue," Yang said. "I can see what you can see, Rubes."

Despite trying to play it cool, Yang's lilac eyes were also wide as she looked at the portal. Rifts weren't the rarest thing in the world, but for one to open up here? Right outside their house? While they'd been sparring, no less? That was a little coincidental. And by a little, she meant a lot. A lot coincidental.

"Should we tell someone?" Ruby asked, at a complete and total loss.

Yang turned a sharp look her way. "You kidding? An undocumented F-Tier Rift, just to ourselves? This is our chance!"

"Our chance?"

Despite the hesitance in her voice, Ruby knew perfectly what Yang was getting at. How couldn't she? The two of them had been on the huntsman-applicant waiting list for ages. They'd been holding their breath for the day they could try their hands at a Rift and take the first step toward becoming a full huntsman. But the truth of the matter was that there were a lot more applicants than there were low-tier Rifts available. At least, ones the Huntsman Association would allocate to applicants. Most went to actual huntsman, who needed to grow stronger.

"Hell yeah, our chance," Yang repeated. "We skipped our way to the front of the line. Got lucky for once in our lives." She started looking around and patting her pockets, as if checking to see what she had on her. "You ready?" she asked.

"Ready? Now?"

Yang grimaced. "Guess we should leave a note for Dad, at least. But yeah. Now."

Her heart started pounding in her chest. But while excited to dive into her first Rift, she couldn't help but be a bit apprehensive, too. "We're supposed to report it," she said. "Not just go into them. We'll get in trouble."

"And?" Yang said. "What're they gonna do? We'll be coming out with classes and semblances. As people that matter. There won't be any real consequences, just slaps on the wrist."

Ruby worried at her lower lip. "You sure?"

"Positive. I'ma go write a note. You grab food and water."

Seeing Yang turn and jog toward the house, Ruby was spurred into motion. And besides, Yang was right, wasn't she? Ruby might have far less of a rebellious streak compared to her reckless big sister, but even she didn't have to think long and hard about breaking the law in this instance.

Mostly because they deserved a Rift. Their combat scores were some of the best on Patch—they just didn't have famous huntsmen parents, or were rich, or have connections of any kind. Sure, they'd eventually be called to an active low-tier Rift, but it had already taken long than Ruby would prefer: three months past her eighteenth birthday, the minimum qualification for an applicant.

Yang had been waiting much longer, but part of that had been her choice. She'd taken a year-long hiatus, and when she'd gotten back, she had decided she might as well wait to do her first with Ruby.

Inside, Ruby frantically packed away food and water. As far as preparations went for Rift delving, all that was crucial were the bare necessities—sustenance, in case the Rift was a long one. Weapons and gear didn't matter, not as first-timers.

There were also ways the Huntsman Association tracked Rift openings, so they didn't have time to waste. They had to enter before officials rolled up. Less than three minutes later, they were standing in front of the black portal again. Ruby with a backpack of simple preparations, and Yang having left a note to Dad on the kitchen counter, where it couldn't be missed. Though with a Rift hovering in his backyard, and his two huntsman-aspirant daughters missing, Ruby would really question his deduction abilities if he couldn't figure things out himself.

Though he probably wasn't going to enjoy being questioned by the Huntsman Association agents, asking them why the portal in his backyard was illegally occupied.

Sorry, Dad.

"Ready?" Yang asked one more time.

"Ready," Ruby said.

They stepped in together.

***

The transition from real-world to Grimm-world was supposed to be natural, even for first-timers. They were supposed to sink into the inky-black otherworldly gateway and have their next step land inside the pocket dimension holding Grimm. Conscious. Aware. With all of their belongings attached to themselves.

That didn't happen.

Ruby kept her awareness, at least. She didn't fall unconscious and have to struggle back to a lucid state. But there was something jarring about the transition—something wrenching and disorienting, that she was pretty sure shouldn't happen. Not by any of the reports she'd read.

When she stumbled to a stop inside the Rift, several things had changed.

First, her belongings were gone. Not that they had made many preparations, but even the scant ones they had thrown together had disappeared during the jump through dimensions. No food and water. Hopefully the Rift wasn't long, or would provide them what they needed.

Secondly, all of her belongings were gone. Including her clothes. Every scrap of fabric that had been keeping her modesty had vanished. Not that she noticed that right away. Her abrupt nudity took a backseat to everything else. Only a remote part of her was aware her body had been exposed.

Her only company would be Yang, anyway, her subconscious told her. No big deal, right?

Thirdly, and most importantly, was the arrival of her class.

The notifications that sounded off inside her head weren't the surprising part. Everyone knew how classes and semblances worked, and how the System would speak into their head when something important happened. Receiving a class was the reason she and Yang had so eagerly broken the law and entered the Rift to begin with. Those supernatural abilities could only be gained by entering into these dark, Grimm-infested places. It was the goal of many young men and women.

Rather, it was the notifications themselves.

***

Class assigned: [Reaper]

Class assigned: [Lust Reaper]

***

A person had one class. That was the simple, absolute truth of the matter. They could have plenty of Semblances—magical abilities that fleshed a class out—but a class was a category, the defining title of a person, and a person could only have one.

Ruby had gotten two.

Somehow, that reality-breaking realization was the second weirdest thing that happened in those few seconds after stumbling out of the Rift.

In the disorientation, Ruby didn't even feel it happen. Or maybe it happened too quickly, or even instantly. Either way, she was only aware of the end result. The new bundle of hyper-sensitive nerve-endings.

Down between her naked thighs, a soft new organ had sprouted, hard and at attention.

Ruby had grown a cock.

A huntress-in-training knew how to take a situation in stride, no matter how strange. Rifts were filled with unknown terrain and deadly Grimm. Adaptability was a key aspect of any curriculum seeking to foster warriors who could hold their own against such threats.

So growing a cock?

Well, no, that was beyond the expected parameters. Ruby's brain came to a screeching halt, and she stared down at herself, expression morphing into part-disbelief, part-horror, and part-pure-mortification.

Because she wasn't alone inside the dark stone cavern that served as the Rift's starting point.

Her sister said, "Uh, Ruby?"

Ruby didn't respond, staring down at herself.

"Ruby, you have a cock."

That statement hung in the air for what had to be a solid ten seconds.

"C-Captain Obvious to the rescue," Ruby said, mirroring her sister's words from earlier.

As if to emphasize her coming back into even a halfway sort of lucidity, her cock throbbed, twelve inches of solid girldick bouncing between her thighs. A powerful, virile motion.

Ruby finally tore her eyes upward and off of herself.

Only to be met with a very naked Yang.

There were a lot of things Ruby knew about her big sister. That she was loud, reckless, assertive, and brimming with endless confidence—and more than that, that she was a great person, let alone a great sister. Yang was someone Ruby could confide in without question. Ruby knew her hopes and fears, more or less, and what made her tick. They were family. And closer family than most. Yang had literally saved her life, once. Been there whenever she needed. They even shared ultimate aspirations.

One thing Ruby hadn't known, however, was how Yang looked naked.

Her popularity with boys suddenly made sense.

Not that it hadn't already made sense—the way she crammed a t-shirt obscenely full had given plenty of hints—but it made extra-sense now.

Yang…

Yang had nice boobs.

And thighs.

And stomach.

And…

Well, dang it, everything.

Her big sister was hot. Like scorchingly so. Her body was amazing.

Her cock throbbed in agreement.

Her cock throbbed in agreement?!?!

Ruby went dizzy. It was just too bizarre. If Yang hadn't rushed forward to grab her, she would have cracked her skull against the stone floor of the cavern. But Yang did. Of course she did. She was always there when Ruby needed her.

Her breasts pressed into Ruby's shoulder as she helped steady her.

"Ruby? Rubes? You good?"

"Y-Yang! What— what— what—"

"Hey, calm down, it's fine," Yang said. "I mean, fucking weird, super fucking weird, but—"

"Weird?!"

"Not you! Not that! I don't care if you have a—! Just—?"

Ruby was hyperventilating. "Yang, why is there a— a— thing between my legs?"

"Relax. Rifts can be weird. We already knew that."

"Not like this!"

"Not like this," Yang amended. "But seriously. Calm down. Please? I'm here. You're safe. I promise."

The serious tone of voice snapped Ruby out of her panic. She steadied her feet, and Yang let go of her, though hovered nearby in case her knees went wobbly again.

The two of them stared at her cock.

Her sister stared at her cock.

That wasn't the kind of thing she could just deal with. If she'd been in her regular body, naked, she'd already be embarrassed. Because compared to Yang? Ruby didn't have 'curves in all the right places,' not like her sister did. It was admittedly a source of insecurity. She didn't think she was ugly, but growing up in the shadow of a goddess? It had left one or two marks.

Her sister was way too hot.

Her cock throbbed in agreement.

Her cock throbbed—?!

She ignored it, this time. Very, very, very pointedly ignored it.

Struggling for any sort of calm rationality she could muster up, Ruby said, "Um. Okay. What the heck is happening, Yang?"

"Good question," she said. "Good fucking question." She was quiet for a moment. "Well, to start off with, what class did you get?"