The Straw Hats had spent the past few days after sailing out from Water 7 generally goofing off and having a good time. At one point, though, Nami reminded Itachi of the promise he'd made to her. Now that he was an official crew member and they were clear of the Navy, it was time for him to keep it. He summoned all of the Straw Hats to the dining area, and told his tale.
"Listen, everyone. It's time you all knew the truth about me. My past, where I come from, and why I can do the things I can do. The truth is, I wasn't actually born in this world. I'm from a different realm entirely, a realm vastly different from this one. In my previous life, I was a shinobi, a ninja tasked with the protection of my village."
He went on to explain everything: the chakra system that he used to cast his jutsu, a breakdown of his Sharingan and Mangekyo Sharingan powers, his upbringing as an Uchiha, the circumstances surrounding the Uchiha Massacre and defection to the Akatsuki, and how he finally succumbed to an illness he had contracted while fighting his younger brother, Sasuke.
"When Sasuke's face faded from view, and everything went black, I thought that I was dead. But then, I woke up on an island not too far from Water 7, stumbling across Marco of the Whitebeard Pirates. They took me in, and, well, you all roughly know the rest."
The whole room was stunned. It was quite an incredible tale.
Zoro was the first one to speak up. "Well, I don't think you have any reason to make any of that up. Even so, coming from another world is such an insane concept. I don't know if I can fully wrap my head around it."
"Yeah, it sounds really weird, but also really awesome!" yelled Luffy. "So you're actually a ninja, and you come from a whole world of ninjas, and you're also like this super-ninja who's super strong even compared to other ninjas?! That's so cool!"
"So let's say we believe you," said Nami. "That still doesn't explain why you came looking for us. You were a member of Whitebeard's crew, the strongest one in all the seas, just like Luffy's brother, Ace! Why would you leave and come be on our crew instead?"
Itachi was prepared for that one. "The reason I sought you all out initially is because the Void Century is my only remaining lead in my investigation into how I ended up in this world, and Robin was the only person I knew about whose assistance I could seek out. But now, I have another reason for wanting to be here. Like I just told you all, my family was more than a little warped. My father even planned a coup d'etat against our own village. Being around you all, and seeing the genuine care and trust you all show each other, is incredible. I've come to think of you all as the family I never had back home. I understand if you don't want someone who killed his own family around, but if you can bear to keep someone like me, who has committed so many unspeakable crimes, I'd like to continue to be a part of this crew."
"All that stuff is in your past, right?" asked Luffy. "You wouldn't do it again, so why wouldn't we want you here?"
That had been almost two weeks ago. Since then, Itachi spent his days generally having fun with the crew. He was still happy to help out wherever he was needed, but he mostly preferred to spend his days assisting Robin with her archaeological research; poring over books, taking notes, and deciphering archaic texts with her in an attempt to piece together more information about the Void Century. The Sharingan's ability to memorize essentially anything was very handy for this, as he was always able to flawlessly recall any passage from any book they'd been over when needed. Even aside from working together, Robin simply enjoyed his company. Since he had recently acquired a taste for coffee, she enjoyed recommending new blends and flavors for him to try, which Sanji was more than happy to brew for them, even if he was less than thrilled at the amount of time the two were spending together. But that was just standard Sanji behavior.
Speaking of Sanji, it came up in conversation that Itachi's least favorite food was steak (this is actually canon, look it up), and since Luffy's presence demanded various meats be in-stock at all times, Sanji took it upon himself to try and come up with a steak he'd actually enjoy.
At present, Usopp was attempting to catch octopus from the fish tank Franky had built into the ship. Itachi was lounging on a bench below deck, reading a book on swords he had bought from a shop in Water 7 while Nami was grabbing some drinks Sanji had made for her and Robin. The girls were sitting at a table in the middle of the room chatting. He was dressed in his normal attire, save for his cloak, which he had left in the men's quarters. He only acquired it to hide his identity without wasting chakra anyways, so now that he was a Straw Hat, he figured he'd need it less and less in the future.
Finding his new sword, Sasuke, had prompted him to start studying the various Grade Swords: their properties, reputations, previous owners, etc. He was reading a section on the Black Blade Yoru. Itachi recognized it from his encounter with Mihawk. Apparently it was one of the twelve Supreme Grade Swords, putting it on the same caliber as his former captain's weapon.
"What the hell? Usopp, are you okay?" gasped Nami, taking Itachi out of his book. He looked up and saw her next to him staring into the fish tank, and followed her gaze. Usopp had been ganged up on by the crowd of octopus and they were latched onto his body, covering him almost completely. Robin raised her hands, intending to use her Devil Fruit powers to assist, but then several of the octopus sprayed their ink, blackening the water and obstructing everyone's view. Itachi bookmarked the page on Yoru, then stood and began forming hand signs.
"Don't worry, I've got this. Water Style: Great Geyser!"
The water in the tank rushed upward, carrying Usopp and the octopus with it and forcefully ejecting them through the hatch on the deck. Usopp hit the deck with a thud, and Itachi and the girls went topside to observe the scene. Luffy and Chopper were picking the octopus off of Usopp one by one, leaving behind red ring marks on his skin and causing swelling.
"Itachi, what was that all about?!" yelled Usopp. "You coulda killed me!"
"You're free of the octopus now, aren't you? Seems to me like it all worked out fine," replied Itachi with a sheepish grin.
"That's not the point!" countered Usopp as Luffy plucked an octopus off his face. "Ow, that hurts!"
"Hey, everyone!" came Zoro's voice from the speaker on the mast. "There's something in the water!"
The crew turned their attention to starboard. There was a barrel floating in the water a few meters away, bound by rope and bearing a banner atop it with a message written across it.
The crew snagged it with their net and dragged it onto the deck. Luffy was excited, thinking it contained treasure, but Nami informed them that it was probably a traditional offering to the sea gods and most likely contained booze and preserved food. Luffy cracked it open, and it turned out to be none of those things. As soon as the barrel lid was unsealed, Itachi could smell gunpowder. Before he could react, though, a huge explosion was triggered, sending a signal flare high into the sky.
"Oh, that's probably not good," Itachi deadpanned.
Zoro laughed at Luffy. "Guess the sea gods weren't too happy with you taking their booze!"
"It could just be a prank, I suppose," pondered Robin. "But if it's not, then we may have alerted someone to our presence, and they're gonna come looking for us."
Usopp predictably freaked out. "You mean the booze was a lie? And worse, it was a trap, and we set it off? Chopper, search the area!"
Nami looked distracted by something else. She was muttering to herself about the air pressure feeling weird, and the clouds moving faster than normal. A storm was coming! She ran up the stairs, ordering everyone to prepare to head south by southwest.
Before long, the storm was on top of them, stirring the ocean waters, bringing heavy rain down on them, and threatening to strike them with huge bolts of lightning. The headwind was threatening to capsize them, so Nami ordered them to furl the sail and use the paddles instead. Itachi and Sanji got to work on the main mast while Zoro raised the foremast. Franky took the helm and engaged the paddles, stabilizing the ship and allowing them to safely sail until they made it out of the storm.
Strangely enough, even after getting clear of the storm clouds, the sun still didn't come back out, and a thick fog engulfed their surroundings. Nami realized they must have sailed into the Florian Triangle. While most of the crew was teasing Usopp with stories of ghosts and disappearing ships, Itachi made his way up the stairs, sensing something was off. In the distance, he spotted a large vessel approaching through the fog. The figurehead looked horribly damaged, and the sails were tattered. Singing could be heard from the deck.
"Captain! We've got an incoming ship on our six!"
As the ship approached, everyone spotted what appeared to be a skeleton with an afro and top hat on deck, a teacup in its hand. Usopp and Chopper were scared out of their wits, and the rest of the crew was on edge. Save for Luffy, of course.
"Did you see that?! There was a singing skeleton on that ship!" exclaimed the captain, moving to board the mystery vessel. Sanji stopped him, saying it would be unwise to go alone. Zoro offered to draw straws to see who accompanied Luffy. Two would go and the rest would stay behind. Itachi and Nami drew the short straws.
On board the mystery ship, the trio came face to face with the skeleton they had seen. He offered a polite greeting, apologizing for not offering a proper greeting sooner. Apparently he was slightly afraid of humans on account of not having seen them in so long. He then took notice of Nami, complimenting her on her beauty. It was actually pretty smooth, until he straight up asked to see her panties and received a kick to the head for his troubles.
"This is certainly a strange development," noted Itachi. "If he's a skeleton, how did a kick cause swelling?"
Luffy was laughing at the scene playing out before him, asking if skeletons pooped, to which Itachi simply facepalmed. "Don't you think we might have more important questions to ask?"
The skeleton stood, grabbing his teacup and cane while humming to himself. "Yes, I poop."
"Not dignifying that," replied Itachi. "Allow me to get right to the point. Are you really a skeleton, and if so, how can you talk and walk around? Are you undead, perhaps a zombie or a reanimation?"
"Hold on, I have a more important question," said Luffy, walking forward. "Will you join our crew?"
Nami was shocked at that. Itachi also couldn't conceal the surprise on his face.
"I'd love to," replied the skeleton.
Back on board the Sunny, the skeleton introduced himself as Brook, stating that he would be their newest crew member, to the skepticism of most of the others. Immediately upon noticing Robin, he complimented how lovely she was and once again asked to see her panties, to which Nami responded by throwing one of her boots at his head.
Usopp, who had disappeared a moment ago, emerged from below deck wearing a bandolier of garlic, a banner with an inscription written on it, a wide-brimmed hat with a plume, and brandishing a gold crucifix and prayer beads. Itachi wondered where the hell he even got most of that stuff.
"What the hell is this thing and why is it on our ship?!" yelled Zoro.
"He's our newest crew member! Isn't he funny?" replied Luffy.
"Who cares?! He's not joining our crew!" He rounded on Nami and Itachi, who were standing next to each other off to the side. "You went with him so he wouldn't do stupid stuff like this! What the hell happened?!"
"Sorry, we messed up," they said in unison.
Later, over an octopus-themed dinner, Brook explained his situation. He was once a man who ate the Yomi Yomi no Mi and was given a second chance at life after dying fifty years ago, but it took his soul a year to find his body on account of the thick fog that constantly loomed over this part of the sea, and by then it had fully decomposed, leaving him as a living skeleton.
Nami held up a mirror to Brook, prompting him to freak out, and for the crew to realize he had no reflection, and furthermore, no shadow. Brook further explained that while the reason he gave for being a skeleton is true, his lack of a shadow is a different story. It was stolen many years ago, leaving him unable to stand in the sunlight without disintegrating into ash. As a result, he ultimately had to decline Luffy's offer, stating that he could not leave the Florian Triangle until he found the one who stole his shadow and got it back.
Luffy, of course, offered to help Brook track this person down and retrieve his shadow, but he surmised that the person responsible would be nearly impossible to find. He offered to play some music for them as thanks, but then a ghost appeared through the wall, causing him to panic and rush his way topside.
The crew began to follow him, and as Itachi stood, a strange feeling overwhelmed his body, preventing him from moving. The only ones who noticed were Chopper and Robin. Everyone else was too preoccupied with trying to catch up to Brook.
"What? What is this?" he asked himself. "My body feels so heavy all of a sudden."
"Itachi, what's wrong?" asked Chopper. "Hey guys," he called out, "something's up with Itachi!" No one seemed to hear him, though.
"Itachi, are you okay?" asked Robin.
"I… I don't know," replied Itachi through gritted teeth. "It feels like something is trying to pull me away. Something I don't have the strength to resist." He collapsed, rolling over onto his back. His breath was shallow and short. Beads of sweat began forming on his head.
"Itachi!" cried Robin, dropping to her knees and leaning over him. "Chopper, get the others! Something's seriously wrong!"
"Robin, I feel… I feel like I might be dying. I don't know what's happening."
"Stay with us, please!" she cried. "Don't you dare leave us!"
Itachi was struggling to think. What was this feeling? What was happening to him? This wasn't the illness he had contracted in his past life; it felt vastly different. He remembered his conversations with Orochimaru, back when he was still a member of the Akatsuki. Something about a jutsu that allowed one to call back the souls of the dead. Was that what was happening here? Had someone cast that jutsu back home, calling him back to it? That was the only thing he could think of to explain this pulling feeling in his chest, as if something was trying to tear his soul from his body.
"Robin," he said weakly. "Don't worry, I think I know what this is."
"What, Itachi? What's causing you this pain?" cried Robin, tears streaming down her face and falling onto Itachi's.
"Back home, there is a forbidden jutsu, called the Edo Tensei. It allows the caster to revive and control the dead in a sacrificial body, placing their soul inside it. I believe someone has cast that jutsu, and is attempting to revive me."
"So you're going to be an undead puppet under someone else's control? How are you going to get back?"
"I have this under control. I left behind a contingency plan before I died, in case something like this happened." He reached up, placing a hand on her face. "Don't cry. I won't be gone long. I promise I'll take down whoever cast the Edo Tensei, and come back to you all. Just take care of my body while I'm gone. I don't want to end up like Brook."
"I will," replied Robin, wiping her tears away and forcing a smile for Itachi's sake. "But you better make sure you come back to me, Red Eyes."
"I'll be back soon, Devil Child." Itachi could no longer hold on, and his soul left his body, crossing time and space back to the shinobi world.
Chopper laid his head on Itachi's chest. He could hear no heartbeat, but his body temperature wasn't dropping. He proceeded to check other vital signs and perform several reflex tests.
"This is weird. His body is dead, but its temperature isn't dropping at all. He's not responding to any stimuli, but it feels strange. If he really got called back to his home world, do you think he'll really be able to come back to us?"
"Of course he will," replied Robin, standing up and putting on a brave face to comfort Chopper. "He promised he would. He said he had a plan. Besides, he died once and got sent here, so there's no reason to think it won't happen again. Now come on, help me move him to a bed. He should at least be comfortable when he gets back."
When he awoke, Itachi was walking along the shore of a lake at the crack of dawn, and apparently someone was leaning on his shoulder for support. He looked over and saw a haggard-looking man with long, white hair and lavender eyes with a ripple pattern.
"I recognize those eyes," he said. You must be Pain, the leader of the Akatsuki.
"Indeed I am, or at least I used to be. Pain was obviously just an alias; my real name is Nagato. And you're Itachi Uchiha."
"So, the caster of this jutsu revived you as well? How many others were brought back?"
"Dunno," admitted Nagato. "I only gained consciousness a few moments ago myself. Sorry to use you for support like this, but my legs don't quite work right."
"Don't worry about it," replied Itachi. "We need to figure a way out of this. Someone is forcing us to do their bidding, along with who knows how many other shinobi."
"Could it be Orochimaru?" asked Nagato.
"I doubt it. I sealed him within my Totsuka Blade. It was one of my last acts in this world before I died. Someone else must have learned the secret of the Edo Tensei, or he passed it on to someone."
"Either way, we're gonna be forced to fight someone before long. That's the only reason anyone would cast the Edo Tensei to begin with. If I could use Rinne Rebirth to truly resurrect you, you'd be free of the caster's control and would be able to go after them."
Itachi thought about Luffy and the others back in the other world. Being fully revived would keep him from getting back there. "This is fine as is, I'd rather not be fully brought back to life if possible. I have a plan to break free, though. I just hope we run into the right person."
"Yeah, me, too. The dead shouldn't be wandering this world doing the bidding of some warmonger."
Several hours passed as Itachi and Nagato continued to make conversation. Might as well enjoy whatever company was available while the caster of the Edo Tensei was allowing them to keep their personalities.
"We've been walking for quite awhile, ever since the sun began to rise. It should be time to fight, then."
"Yes," agreed Nagato. "But who are we fighting against?" Nagato paused, as though he sensed something. "No way…" he breathed.
"Are they close?" asked Itachi.
"Something feels familiar; nostalgic."
Then, a man cloaked in an orange chakra aura and one wearing standard Kumogakure gear with several short swords worn across his body emerged from the forest, stopping when they spotted them.
"Itachi Uchiha?! Nagato?!" exclaimed the man in orange, whom Itachi recognized as Naruto Uzumaki. Talk about a stroke of pure, golden luck.