So I'm finally getting into Phantom Thief Joker. And I plan on having some fun with this. So here's how things are gonna work. I've already written out how the treasures from the Joestar Collection are going to appear. Now this will be split into two parts. Chapters 1-30 will take place during the events of the third arc in Jojo New Universe: Jojolion, while 31-58 will take place during Cruel Angel's Thesis and will be written out after that Part has been resorted. Let's get started, shall we? Disclaimer: I don't own Jojo's Bizarre Adventure, the Persona series or any other referenced media.

First Caper: Shadow's Trump Card, The Star of Auldale

It was just another day for Speedwagon Foundation intern Ren Amamiya. A normal middle school student at fifteen, Ren had taken up the internship in preparation for high school. Already an academic genius, many schools were showing an interest. Many of his classmates even gossiped that he might be in line for Hope's Peak Academy. But he sincerely doubted he had the talent necessary for that. Still, it was nice to know they had faith in him. Right now he was taking notes on some of the exhibits in a special museum dedicated to the Joestar Family and all of its accomplishments.

Ren stopped in front of a set of eighty-four treasures from the history of the Joestar family, known as the Joestar Collection. Just as Ren finished his notes, a sudden blaring could be heard throughout the museum. He looked up just in time to see the roof coming down on him. A group of mysterious figures landed on the rubble. "I think someone was underneath all that," one said. "It doesn't matter," another said, "Here's what we came for." They smashed into the display case for the Joestar Collection and immediately fled with it.

Once they were gone, Ren seemed to phase through the rubble, accompanied by a red humanoid demon with black, feathery wings. This was Ren's Stand, W Boiled Xtreme. "So someone decided to steal directly from the Joestars," he muttered to himself, "Just who were those people? And what did they want with the Joestar Collection? I'd better report this to Mister Dashell..." Just then, he saw something unusual. A velvet blue door embedded in a nearby wall. 'That wasn't here before... I wonder what's inside.'

Inside, Ren found what looked to be some sort of bar or guild hall. Sitting at a large table was a lanky man with white balding hair and a surprisingly long nose, wearing a suit. Standing next to him was a young woman with short blonde hair and a velvet blue blazer with black leggings. "Pleased to make your acquaintance," the man said, "I am Igor, the caretaker of this establishment. This is my servant, Margaret." "A pleasure," Margaret said, "We noticed how you survived the collapse of the roof caused by those criminals."

"Yeah," Ren said, "I was just about to inform my superiors." "A noble action to be sure," Igor noted, "But those criminals are counting on Speedwagon trying to find them. I'm not sure what their true goals are just yet, but I do know this much... They intend to show dominance over the Joestar family that has defeated so much evil in the past. From the vampire DIO Brando, to the Idea of Evil itself, Angra Mainyu. Stealing the treasure collection that represents their accomplishments would show that someone was above them... Unless someone was willing to steal it back."

Ren realized what Igor was getting at. "You think I can pull it off?" "A Stand user capable of phasing through solid objects would certainly be more than capable of succeeding," Igor noted, "And I'm sure your Stand is quite versatile too. If you're concerned that a young man your age would be unable to pull it off alone, then fear not. I am willing to aid you in this endeavor. You see, I am entity that exists between realities, and as such I can peer into reality and observe the lives of others. In other words, I can help you locate the missing pieces. What do you say?"

Deciding he really had nothing to lose, Ren decided to go for it. And his first task, getting the right look. In truth, W Boiled Xtreme was not just about phasing through solid matter. He was capable of manipulating shadows, sinking into them or manifesting them as attacks. His senses were also far sharper, to the point where he could easily pick out a Stand user in a crowd. He used his powers to fashion himself a special outfit, black with red highlights, a long coat over a vest with a bird mask over his face. He looked himself over in the mirror. "The perfect image of a phantom thief. Now for the first score..."

Already it seemed the Joestar Collection was being scattered across the world, though Igor had tracked one particular item to a luxury cruiser resting off the coast of Manhattan. Flying there was simple thanks to Ren's Speedwagon internship. He slipped in through the aft of the ship. He was pleasantly surprised to find there would be a masquerade ball being held on the ship for the next few days. 'I'll fit right in as I case the ship for the first piece.' He then noticed a waiter serving drinks. The man had white hair, red eyes, and for some reason wore rabbit ears and a large fluffy tail. Most important of all, he was exuding Stand energy.

The waiter approached Ren. "Something to drink, sir?," he asked, his tone unsettling. Ren eyed the glasses on the tray carefully. There was something unusual about the way they bubbled and fizzed. "Not for me, thanks," he said. He instead walked over to the punch bowl. He noted that several people who had accepted drinks from the man were starting to feel ill, while those who only drank from the punch bowl seemed just fine. So he took a quick drink for himself, nodding as he confirmed the punch was safe to drink.

He noted that the ship seemed to be owned by a local mafia family. It wasn't long before he found exactly what he was looking for, a sapphire necklace known as The Star of Auldale, once owned by Renaissance noblewoman Auldale Joestar. He carefully scanned the security around the glass case using W Boiled Xtreme. 'Hmm... Nothing truly noteworthy. Just a silent alarm connected to the case itself, protected by a genetic lock. I can make anything I touch as intangible as me, so slipping The Star of Auldale out shouldn't be a problem. I just need to plan my escape route. And make sure to plan for if they have the necklace moved.'

Ren carefully slipped through the doors of each room on the cruiser, specifically looking for the ones belonging to the mafia heads currently on the ship. He had earlier found the guest registry and matched the names to the Speedwagon database. In one of the rooms, he found something interesting. A ship manifest that included, for some reason, an assassination request from someone named "Usagi". 'I don't recall seeing that name on the registry... Unless he's disguised as one of the staff.' His thoughts quickly returned to the mysterious waiter who radiated Stand energy.

"Usagi is the Japanese word for rabbit," he noted, "And that waiter was dressed a little like a rabbit. I'll have to keep an eye on him. Might be worth investigating the staff rooms." He carefully slipped into the rooms, blending into the shadows to avoid being spotted. 'No sign of that man... I guessed as much. I need to find where he might be staying. Those drinks he was serving don't match anything that was on the buffet table. I've worked with Speedwagon long enough to catch the telltale signs of poisoning.'

Ren soon found himself inside the luxury suit owned by the family head. Inside was a diary. Ren read through the pages. "Interesting... He deliberately invited individuals he wanted to get rid of. Those that didn't fall to Usagi's poison, would be killed by his special ability. Special ability... Just what sort of Stand does Usagi possess? I get the feeling I'll be finding out once I make my heist. After all, this journal states that Usagi is going to make his move during the second day of the ball, which is tomorrow..."

Just as Ren thought, the "waiter" was really the mysterious Usagi that had been noted on the manifesto. He approached his client, Don Luigi DeBorne. "I think we have an uninvited guest," Usagi said, "Should I take care of him?" "Only if he becomes a witness," Luigi assured him, "My late brother Mario would agree that trying to take out a potential threat, before you've even confirmed it was a threat, is the fastest way to make a new enemy. You remember how Sports Maxx was found dead in Green Dolphin prison."

"Ah yes," Usagi replied, "Somehow he had been forced into the pipes leading to the sewers. Most likely the work of a Stand user he had crossed unknowingly. Well, I'll keep an eye out for our special guest." He grinned, revealing his teeth to have been shaved down until they were pointed. "And if he should interfere with with our task here... I'll give him a good taste of my Stand... Kin Usagi..." He pulled a pair of razor-sharp blades from his giant rabbit tail, chuckling manically.

"I've managed to scope out the entire cruiser now," Ren noted, "All that's left is the heist. But if I'm going to be a phantom thief, then I can't just sneak in and steal The Star of Auldale. I need to announce it. And that means I need a name. One that will grab attention without letting anyone know that Speedwagon is involved..." He was idly shuffling a deck of cards, and raised an eyebrow when he pulled out one of the jokers. "Huh... The joker is a wild card, the ultimate trump. Kinda like how my Stand works..."

He gave a subtle grin. "Yeah, that's perfect. I'll remind the world that the name 'Joker' can mean more than some villainous clown from the pages of DC." He wrote out a neat top hat design with a domino mask for his symbol on a large piece of paper. "This will be the design for my calling card. And since I'm stealing from a known criminal, I may as well go for volume. Time to get ready world..." He donned his thief outfit and placed his first calling card in a copy machine. "Because it's the grand debut of... Phantom Thief Joker!"

Luigi was boarding his cruiser, ready for the massacre of the century, when he spotted most of his guests gawking at the outside of the ship. He gasped when he saw the side facing the port was covered in red cards of some kind. One peeled off in the wind and flew right towards him. He grabbed it and read the message on it. "Luigi DeBorne, I am the Phantom Thief Joker. This evening I will steal The Star of Auldale from your possession." Luigi grew incensed and tore the calling card to shreds before going to find Usagi.

That evening, as promised, Joker was perched on the warehouse near where the ship was moored. There were spotlights going off from the inside, causing him to smirk. "He's daring me to make my attempt. You didn't need to invite me, Luigi. I was already planning on crashing the party." He made a daring leap off the warehouse, dashing up to the cruiser before leaping onto the roof, pulling out a dagger to take out the lights. He then slipped into through the floor towards the ballroom.

He was a little surprised to find that most of the party-goers were now radiating Stand energy when yesterday they seemed normal. Either Luigi had access to an artifact similar to the Stand arrows, or this had something to do with Usagi's Stand. Either way, him landing on the case for The Star of Auldale caught everyone's attention. "So you showed up!," Luigi called out, "Too bad that case is..." "Genetically locked?," Joker interrupted, leaving Luigi flabbergasted, "Yeah, I already know. But luckily... I don't need to pick the lock or break the glass. W Boiled Xtreme!"

Luigi gasped in shock as Joker slipped his hand through the glass case without setting off the alarm, grabbing the necklace and pulling it out like it had been encased in jello. "So you too... That changes things... Usagi! Get him!" Joker spotted Usagi as he came through the crowd, having ditched the waiter uniform for a thong and red high heels. "Aren't those a little awkward for fighting?" "Oh, I won't be doing most of the fighting," Usagi said, "My friends will. Kin Usagi!"

The people that had been radiating Stand energy suddenly revealed themselves to be some sort of zombies as they removed their masks, pulling out various guns and firing into the crowd. Usagi grinned as some of the bullets seemed to impact Joker, only to drop the grin when he realized Joker wasn't dying. "You literally saw me phase through an alarm-rigged glass case," Joker pointed out, "What made you think I couldn't use my Stand to become essentially bulletproof?"

"Not bad," Usagi admitted, "But my friends here can't be killed so easily, either. Chop them up however you like, they can still move about. And they retain skills they had in life. Well, unless any of them were also Stand users." Joker smirked and slipped down through the floor. Usagi frowned before leading his horde to follow Joker. They soon reached the kitchen area. "Something I'm curious about," Joker said, peering out through the shadows, "Would things like ice and fire be capable of stopping your so-called friends?"

Usagi gasped when he saw his horde follow Joker's voice into a nearby freezer. "No! Not in there!" But Joker had already slipped through the horde and shut the freezer door, turning it on full blast. By the door opened again, his zombies had turned to brittle ice that shattered. "Now if you'll excuse me," Joker said, "I believe The Star of Auldale needs to be returned to its true owner. But good luck with your future assassinations." And with that, he phased through the nearby wall, leaving Usagi dumbstruck. "What just happened...?"

"Insurance alone isn't going to replace what we've lost," Joseph Joestar noted, observing the damage from the robbed museum, "That's almost a thousand years of Joestar history, gone in a flash." Shining Armor sighed. "Who could have done this?" "Excuse me, Mister Joestar," came Noriaki Kakyoin's voice as he approached, "This package was sent to us by an anonymous source." Joseph checked the package with Hermit Purple, and opened it when he found nothing wrong.

The three men gasped when they saw what was inside. "The Star of Auldale!," Joseph Joestar said in shock. Next to the necklace was another calling card. "I'm here to return what is yours, Joseph Joestar. Use the number enclosed to reach me if you need any more little chores done. Phantom Thief Joker." Joseph looked at his two friends and they all smiled. Joseph called up the number on the card. 'Greetings, Mister Joestar,' came Joker's voice. "Hello," Joseph replied, "I'd first like to discuss your commission..."

An update on the new Stands.

W Boiled Xtreme (Theme song of Kamen Rider W)
User: Ren "Joker" Amamiya
Ability: Ren can use his Stand to sink into shadows and attack with them, as well as turn intangible to pass through solid objects. His senses are also sharper, especially in the dark, to the point where he can pick up Stand energy.
Power: A
Speed: A
Range: B
Durability: A
Precision: B
Potential: B

Kin Usagi
User: "Rabbit" Usagi
Ability: A pair of twin blades, Kin Usagi will turn anyone it kills into a zombie that the user can control. In turn, the zombies can kill others and make more zombies. They are nearly impossible to kill unless incinerated, frozen, or stripped of their flesh in any manner. Any zombie made will retain the special skills they had in life, save for Stand power.
Power: C
Speed: B
Range: D
Durability: B
Precision: C
Potential: D

Next time, Joker makes ready to steal the second piece of the Joestar Collection. But he learns that another master thief also has his eyes set on it. With detectives and security abound, Joker encounters two new rivals from both sides of the law that will make his life more exciting. And along the way, he makes a challenge for the right to be named "Emperor of Thieves". Read and review.