A/N: If my OCs end up being characters people are actually interested in, I might write a prequel to this.
"We have about two months before Jotaro locks himself up. Kelly, you've still got the arrowhead?" The American teen, Nathan, turned to one of the other two people in the cramped, dry, air-condition-less room.
The 22-year-old brunette decided that this was a rhetorical question and simply pulled out the necklace she wore. It was an arrowhead with an ornate beetle surrounded by the arrow's bladelike tip. The part that would attach it to a shaft was clean and unbroken, wrapped around a number of times with a simple red string. "Considering your plan," she said, with the air of someone at least five years older than she was, "You're going to need it the most, even with Over and Over Again. Ruby, have you finally figured out what your stand does? ...Ruby?"
Instead of the teen they'd agreed to meet six months ago they found a stranger. This other girl wore a serene expression under her wide-brimmed hat. The serene expression turned into a mysterious grin, as she looked at the other two from under her hat.
Nathan was the first to act. He stood up and summoned his Stand, a four-eyed humanoid, stern and confident. "Who are you and where is Ruby?"
The girl took her hat off, letting her black hair fall down to her shoulders. She looked exactly like the Ruby they knew, perhaps a little older, but somehow, for a moment, they were completely unable to recognize her. She leaned towards Kelly, looking her in the eye. "It's a marvel how six months and a silly hat enhances your presence manipulation, Miss Pate. You two should know me better by now." Then she asked Nathan to calm down in Japanese, using the familiar "-kun" honorific.
The spell broke the moment she took off the hat. Nathan's stand disappeared as he stared at her, wide-eyed.
Kelly raised an eyebrow. "So you have the same kind of stand I do?"
The 17-year-old shook her head, almost sadly, before smiling amicably. "No. It's a stand that suits a main character like me."
"And what does it do?"
Ruby leaned back into the wall of the small room, laying her hat on the floor. "There are some rules, but basically, I am now able to copy another Stand's ability if I know how it works and the user is in range."
"So no King Crimson, huh?" Nathan didn't miss a beat, eliciting giggles from his friend.
Kelly didn't get the joke. "You people and your manga references." She crossed her legs under her. "If Nathan did, indeed, play his part, we need to get into specifics. We've established that I will not actually be joining the Crusaders at any point, but since you two won't be able to do what you're trying to do without joining, we need to figure out when, where, and how you're joining the group."
"Well," replied Ruby, "I've made my decision. It will be risky, and I'll need your help, but I honestly believe that if I want to understand Jotaro... I'll have to fight him. I'll be joining with Kakyoin."
Nathan knelt down and looked her in the eye. "Are you sure about this? You do know what it means, right?"
"I'll be fine. I'll trust you and Jotaro." Ruby Megumi gave Nathan the sweetest smile she could muster.
—
No Joestar could be trusted. It was easy enough to keep the act. Pretending that she'd grown scared and run away from His presence. That it was for the better that He did not trap her and impose upon her His will. Her desire and purpose was clear. She would kill Jotaro Kujo. She would bring Him the victory He deserved.
"Though I am but a human, I have sworn my allegiance to Him." That was her cue. While Jotaro was distracted by the nurse Hierophant Green possessed, her own stand began to lay its trap. Were she not trying to kill his grandson, perhaps Joseph Joestar would be proud of how carefully she laid her trap. With her foreknowledge, Kakyoin was already prepared for Jotaro's kiss trick. Hierophant Green freed itself from the woman and shot piercing emeralds from its hands.
"Emerald Splash!" exclaimed Kakyoin, calling out his stand's attack.
Defying her prediction that Jotaro would be helpless to this assault, Star Platinum had his arms crossed in front of him, blocking the barrage.
"What a pathetic Stand. All it's capable of is possessing people and spewing out soaked jewelry." Star Platinum grabbed Hierophant by the head and held it up. "It looks like a melon, and judging by the marks of my fingers on your forehead, I could easily crush it like a melon as well."
Kakyoin winced at the pain, but was otherwise unfazed. He got down from the window. "While you have a hand around my head, you're unguarded. Emerald Splash!"
Star Platinum was quick enough to block the emeralds in front of him with one arm, but Jotaro didn't expect to be assaulted from the side. Before he noticed, a group of red gems collided into his side, flinging him back while another voice announced it as the un-creatively named "Ruby Splash."
Jotaro wiped blood from his mouth when a girl climbed up onto the windowsill. Hierophant managed to escape Star Platinum's grasp and floated up beside Kakyoin, arms crossed like the wooden marionette Kakyoin held.
"Looks like the old man's friend was right. There are two of you."
Ruby stopped for an instant. How did he know...? Then she frowned at Jotaro. "It doesn't matter how you know. I'll kill you as easily as you killed that nurse!"
As Jotaro looked to the aforementioned nurse, red and silver appendages from all around the room began firing red versions of Kakyoin's Emerald Splash at him.
"What-" Jotaro's stand quickly deflected the stand attack with the back of its fist one by one.
"I told you," interrupted Kakyoin, "Attacking Hierophant Green would mean hurting her. Despite its range, my stand is a bit of an agoraphobe, and lashes out when forced from hiding.
"Which means," he explained while pointing at Jotaro, Hierophant launching a barrage of emeralds at the notorious delinquent, "Her injuries are your fault and responsibility!"
"You sacrificed her for your own life." Ruby got up to stand beside Kakyoin. "How despicable."
Jotaro stood his ground as his stand deftly blocked the attacks against him. He narrowed his eyes at his outnumbering attackers.
"I'm a well-known delinquent," he began, he and his stand pushing forward through the continuing onslaught of weird stand gems, "I've picked more than my share of fights and beat my opponents, leaving them with broken bones and lasting scars. I've humiliated one of my stuck-up teachers to the point he never returned to school. I skip the bill at restaurants I find lousy. I'm no model citizen by any means and yet even I..." His stand grabbed Hierophant's wrist, stopping it from spraying its attack. Jotaro himself grabbed the girl's wrist. "Even I know evil when I see it. When you use people, especially innocents, for your own gain. It's you who are despicable! And as your Stands are invisible to the law, I shall be the judge!"
Kakyoin laughed. "Evil? No, evil, as history would remind you, is the conquered. Nothing matters but victory!" Hierophant's tentacles wrapped around Jotaro's stand.
"No matter what, the ends justify the means, and there is no concept of 'fair' in love or war." The red tentacles began to close in around Jotaro. "We'll show it to you first hand!" Ruby grinned, despite her position.
Jotaro was unfazed. "In that case," he said, sliding the tip of his left index finger across the brim of his hat, "I'll prove that you are the evil ones!"
Despite being completely entangled in Kakyoin's stand, Star Platinum punched through his bindings and assaulted Hierophant Green head-on. Jotaro punched the girl once and flung her into her own stand, which dissipated as she passed out.
Jotaro watched his stand do his work, while Kakyoin's final words were "Such power..."
"Fortunately for me, my stand is anything but weak, though I'd say it's more sadistic than I am."
Jotaro and his stand picked up the two people and brought them home, deciding to skip school for the rest of the day. Two against one weren't good odds, but ambushes tended to be less effective when they were known about beforehand.
—
Elsewhere, Nathan sighed in relief. "I can't believe it took three tries just to get Jotaro to listen to me."