Summary: A pleasant surprise born on butterfly wings...

Chapter 8: Butterfly Effect

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Three steps into the Isshin Dojo Luffy stopped, stared, and laughed. It was such a pure, bright, cheerful sound that it brought the entire Dojo to a halt. Save, that was, for the fiercely dueling pair in the center of the floor. Those two were focused so purely on each other that they likely never even registered the sound, even as the rest of the Dojo stared at the unexpected intrusion of a brightly laughing ten-year-old in their midst. Finally, as the young woman slipped a blow past all three of the green-haired student's swords, knocking the wind out of the youth in a blow that was clearly lethal if it had been done with live steel, one of the older men in the Dojo spoke up.

"Something funny kid? And what are you doing here, anyway?"

Luffy grinned hugely at the man, the expression of pure joy on his face disarming any insult the man might have thought he meant by the laugh.

"Just contemplating the wings of butterflies, sir! As for why I'm here, I was hoping for a spar with some of the locals from the Dojo!" He pointed out at the two on the main floor, the green haired youth looking furious even as the young woman looked smug. "Those two seemed particularly awesome!"

The older man's mouth quirked into a grin in response to Luffy's own infectious smile.

"Better believe it, kid. Much as I hate to admit it, both of them run roughshod over most of the adults these days. You might want to challenge someone else, first."

Luffy smirked.

"If I have too, I have too…but if I don't get my ass kicked by the best, how will I know how far I have yet to go!"

The man blinked, then laughed. His own, far deeper laugh finally drew the attention of the two younger students, who stared in disbelief. Luffy guessed that this man must not usually be the laughing type. But that was fine! He seemed nice enough, really! Particularly as he got control of himself and called out to the young woman, amusement clear in his voice.

"Shimotsuki! This kid said he wants to get his ass kicked by the best, so he knows how far he still has to go! Want to humor him? Or did Zoro wear you out?"

Shimotsuki Kuina, the sight of who being still alive had drawn that pure, happy laugh from Luffy, turned curious eyes on him and he grinned brightly in her direction. She seemed taken aback by his cheerful expression, combined with the half-crass comment, and it took her a moment to come back on balance.

"I can give him a match, if he wants one. What is your name, traveler?"

Luffy covered the distance to the floor in a cheerful bounce, holding out his hand to her. She looked completely nonplused as she shook it.

"Monkey D. Luffy! Inventor of the Wave Dancer sword style! Or what will someday become that, at least! I'm still working on it."

Kunia looked, if anything, even more bemused than she had a moment ago. Her eyes flick to the sulking Zoro, who had limped off to one side of the main floor.

"What is it with people thinking building new sword styles is a good idea? Still, it's always interesting to see what people come up with, and you move like you at least know what you're doing. I'll spar with you at least this once. If I do so again will entirely depend on how well you do."

Luffy grinned, giving her a polite half-bow that was at odds with his casualness up to now.

"Thanks! I look forward to seeing how badly I do, so I can fix the problems!"

Kuina's lips twitched, seemingly against her will, at that. Shaking her head a moment later, she backed off and set herself. Her head cocked as Luffy carefully set his hat down outside the sparring area and drew his practice jian.

"That's an interesting sword. I've only ever seen a single one like it before."

"Captain Shanks, right? He was interested in what I was doing and had himself one made. He got me a metal practice blade made at the same time, and spent a lot of time helping me refine the basics I'd come up with before that. He was the one that told me about this Dojo being here, actually. Said this village was where he'd gotten the blades made and that the Dojo Master here was insanely good for the East Blue."

Kuina's eyes had narrowed, sharpening as he casually revealed the connection. There was shuffling of more than a few feet around the Dojo as quiet descended. Clearly, many of the adults remembered Shanks visiting, too.

"I see. So you were trained by the only man to ever defeat my father in my lifetime. I shall take you seriously then."

Luffy nodded, set his own loose stance, then saluted neatly with his blade to indicate he was ready. Kunina didn't waste time, and she was fast. At least as fast as he was, even with it being obvious she was holding something back still. Even so, he had a massive advantage she didn't and had every intention of using it ruthlessly. At least in this opening match. With his Observation Haki going full blast he smoothly parried the first series of strikes, his opponent speeding up as she realized he really was to be taken seriously. His flowing movements, mixing slashes with thrusts and never taking a blow head-on, stymied her for long moments. As she got a feel for his style, however, the fact that he'd had no one to practice against since Shanks and his crew left quickly started to show. In pure spite of his Observation Haki, her greater skill and superior speed began to slip through his guard.

Only the fact that his movement style extended to his body, and that he caught her off guard twice by outright swapping hands, kept the fight going. And then, he finally missed badly enough for her to get a blow properly past his guard and she sliced down on his collarbone. It was a clean hit and he hissed, then drew away and bowed properly to acknowledge that the blow would almost certainly have won her the match. Kuina drew away, but her eyes were alight with interest.

"You're good. Very good. And you have some trick or other that was letting you keep up with my speed. But I think you haven't fought many other sword users, have you?"

Luffy, far from taking offense, just grinned.

"Nope! Haven't had a sparring partner since Shanks' crew left the East Blue two years back. Not for swordsmanship, at least. My gramps is hella strong, but he's a pure brawler. That's why I came to visit!"

Kuina looked surprised, and she was far from the only one, given the murmur that went around the room.

"You haven't had a sparring partner in so long and you still did that well? With a completely new style?!"

Luffy grinned.

"There's a reason Shanks was interested! Besides, as you said, I have a trick or two…"

"Observation."

The voice spoke from an inner doorway and all eyes snapped towards it.

"Father! I…"

The man shook his head.

"You should have gotten permission first, daughter. But the match was a good one. And our young guest an interesting surprise. Care to give me a demonstration, young man? Without the Observation, if you please."

Luffy slowly nodded, and the man grabbed a shinai from a nearby rack and took his daughter's place. Kuina looked shocked, quickly giving up her position as she watched with clear curiosity. Luffy took a deep breath and cleared his mind without reaching for Observation. He'd created a sort of moving meditation which worked well with the flowing nature of his sword style, even if he couldn't yet use it and Haki together. Once he'd fallen into its embrace, he attacked.

The Dojo's master swatted his every strike away with ease, not seeming to strain in the slightest despite everything Luffy could do. So different was their skill that he could feel his own Swordsmanship skill leveling up just from this one match with the man on total defense. Then, with contemptuous ease, he slipped his shinai through a hole in Luffy's guard, it's point resting on his throat. Luffy stilled, then backed away with a much deeper bow than he'd given Kuina. This man was a Master. No question. And he would treat him with the respect that deserved. Thankfully, the man was also smiling slightly.

"My daughter is correct. You have quite a lot of talent, young man. As might be expected from anyone who drew the attention of one of the two greatest swordsmen in the world. You were also correct in seeking out others to refine that interesting style of yours against. You are welcome to stay as long as you are able."

Luffy bowed again, though more shallowly.

"Thank you, master. I'm afraid I can only spend two weeks here at this time, as I am expected back on my home island before the end of the month. If possible, I would like to visit again when I can, however."

The sword master nodded.

"Quite understandable, given your age. And so long as you continue to learn and do not abuse the students here, you are welcome to return to continue testing yourself. I believe exposure to your new style will be quite good for my own students."

With a dismissive nod, the older man quietly gathered up his daughter and headed into the back of the complex, presumably where they both lived. Luffy grinned as they left. This was awesome!

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Luffy just barely managed to dodge around Zoro third blade, scything his own blade low to make the green-haired kid jump. That put his opponent off balance enough for Luffy to get a strike in, causing the man to growl…but back off. Luffy found it amusing how much less losing to him bothered Zoro, though he also understood it. Zoro, after all, beat Luffy two times out of three. Whereas he had yet to ever beat Kuina. It was the young woman, who had been watching the two of them spar, that spoke up after Zoro conceded the most recent match.

"You're not a pure sword user, are you?"

Luffy blinked, looking over at her quizzically.

"No. The style is actually meant to be used with a pistol in my off hand. How did you know?"

Zoro looked surprised, clearly not having noticed, but Kunia merely nodded as if that made perfect sense.

"The openings you leave, that both of us keep taking advantage of. You've tried to close them and sort of succeeded, but the longer I watched the more obvious it was that you were supposed to have something in your off hand. I thought some sort of shield or sword breaker at first, but you would have used those. A pistol makes sense."

Zoro frowned.

"Wait, so you haven't been fighting us seriously?!"

Luffy quickly made a so-so motion with his hand.

"Yes, no, sort of? I've been fighting you seriously as a pure sword user. But, as Kuina noticed, that's not my intended fighting style. I also haven't been using Observation since my first match with her, since her father told me doing so was detrimental to developing the style. I need to develop the core of the style first, then use Observation to enhance my use of it."

Zoro's frown shifted to a scowl at that.

"What the fuck is Observation!"

Luffy considered him carefully. That was…a dangerous question. Less dangerous than Luffy had thought, given that he'd recognized almost immediately Shimotsuki Koushirou could use a measure of Observation Haki himself. But he clearly hadn't explained the concept to Zoro. Kuina didn't look confused, meaning he'd likely explained it to her after she'd seen Luffy use it. Well, it was something he wanted his future crew to be able to use anyway. And after a week of hanging around them, he wanted both of them as his crew, if he could get them.

"It's a part of a…technique set, I suppose you could call them, even if that's not quite accurate. Two of the three can be learned by anyone with a strong enough will and are generally what separate the highest level of fighters from the next tier down. If you two are truly serious about one of you becoming the World's Greatest Swordsman, you'll have to learn it at some point. Both of the two that currently via for that title are masters of Haki. No one who isn't at least an expert with both types is ever going to topple either of them."

Even Kuina had perked up at that, eyes narrowing. Apparently, her father hadn't mentioned that little detail. Time to rub a little salt into a very specific wound while he was at it.

"It's also why little things like gender are basically irrelevant at the highest levels. For the most part, whoever has the better combination of skill and Haki wins in high-level battles. Between people like the Yonko or Marine Admirals, that is. Devil Fruits can also help…but Haki mostly counters those, anyway."

Kuina looked…constipated, honestly. It was sort of a funny expression. Even if he was pretty certain it was because she was trying to suppress a bunch of conflicting emotions. He gave her some time to process by continuing to explain.

"Haki is effectively Will made Reality. Or Spirit if you prefer that term."

Luffy raised a covered it in Armament Haki, his fist turning black. He pulled a knife out of his pocket, tossing it to Zoro.

"Zoro, try to slice my palm."

Zoro's eyebrows rose, but he complied. He snapped the folding knife open, tested its edge for a second, then slashed at Luffy's now-open palm. He and Kuina both blinked as it failed to do any damage. Luffy quickly let it lapse.

"Don't mention I can do that to anyone. It's virtually unheard of for anyone to be able to use even one type of Haki outside the Grand Line. Me being able to use both the learnable types would mark me as a major target for the World Government. I'd rather not deal with that for a few years, at least."

Thankfully, both of them nodded, even as they still looked amazed at what he'd shown them. He picked up his explanation while they were still processing.

"That was Armament Haki, essentially willing your Spiritual Energy to protect you from harm, like wearing a suit of armor over your skin, only better. Dracule Mihawk is one of the world's greatest masters of it, his Black Blade being a sign of that fact. It wasn't forged that way, but turned permanently to that color by infusion of his Haki over time. It's something only a true master of Armament can do."

It was also something Luffy hadn't known, before training with Shanks. It had been relatively easy to get the man to talk about his rival. He clearly respected Mihawk and had spoken at length about Yoru, Mihawk's blade.

"I'm actually better with Observation Haki, but it's less showy. What it does is essentially let you use your Spiritual Energy to read people, or any living thing really, around you. At the highest levels it can supposedly grant you actual precognition, seeing a few moments into the future. At the level I can use it, it just gives me an insane reaction speed, since I can feel your movements as you're making them, instead of having to wait for my eyes to translate what they see."

Kunia, with a speck of hope in her voice, broke into the explanation.

"How do you learn?"

Luffy winced, sighed, and scratched the back of his head.

"I can give you a couple of exercises that will help, but actually unlocking it is…well, there's a reason it's so rare. I think both of you can probably do it, but don't expect it to be fast. It could take years, if you manage it at all. The fact that I can do as much as I can is because my gramps is insane and put me through training that almost killed me. Like tying me up and throwing me to giant tigers sort of insane. Can not possibly recommend."

It actually had killed Luffy. But he wasn't going to tell them that. The longer he spent thinking of himself as Luffy, the harder it was to remember anyway. Three years after his replacement of the original, he only had brief moments of thinking of himself as Alex. Usually only when he was working on plans to replicate something from Earth, to be honest. Like the catamaran, or the blueprints for a revolver sitting in his inventory.

Zoro looked like he'd have been willing to try it, but Kunia shook her head.

"I'll take the exercises, thanks."

Luffy laughed at her deadpan delivery, having slowly gotten used to her relatively subtle form of emoting. He gestured to the tree near their usual outdoor sparing spot.

"Come on then, I'll show you. I'm afraid their pretty boring…but important. If you're really serious about that goal of yours."

Twin pairs of fiery eyes met his, showing them just how dead serious they both were. He smiled. Yes, he was going to do his best to get these two aboard his ship. They would need to travel to get better at some point anyway, and the fact he wasn't going to dive straight into being a pirate would likely help in recruiting them. For now, he needed to prove he was someone they would want to follow. Showing the ability to make them more powerful was a good place to start. He only had a few more days before he had to head back to Foosha lest he be missed, but he would use them as best he could…

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A/N 1: Luffy's age here is roughly ten and a half. I should also probably have noted this before now, but the timeline might not be perfect to One Piece's events. I've done my best to keep things loosely in line with known events, but some of them are either very nebulous when they actually happened, or needed to be shifted slighly for one reason or another.

A/N 2: Kuina's death was another thing like Shanks' arm loss. It made zero sense. One of the first things they teach you in any martial art is how to fall. And it becomes Instinctive by the time you advance very far. The idea of a fall killing a budding talent in swordsmanship is so unlikely it falls into the '1 in a billion' type of freak happenstance. As such, I figured even the most tiny and minor of butterfly effect could alter that freak chance. That it will make Zoro less of a whiny, melodramatic, angtsy sort is just a bonus.