Teaching Luffy how to read and do basic math had been a medium-grade miracle that had taken the combined efforts of Makino and Ace years to achieve – he hadn't learned how to read until he was twelve. To this day, he could generously be said to have the reading comprehension of your average ten-year-old. By most anyone's metric, Luffy was an idiot.
Academically, it was true. Luffy would never be able to grasp complex ideas or abstract thoughts. The scientific method was lost on him, because he would lose track of what he'd already tried or get bored of doing things in order. Whether it was because his rubber brain had trouble conducting electrical signals or, more likely, he'd just always been that way, Monkey D. Luffy would forever be a moron.
On the other hand, he was a monster of kinesthetics. When it came to mastery of his own body, it could quite literally be beaten into him. Give him a strong opponent to fight and you could almost see him getting stronger.
That was what his grandfather had done for him. It was how he got so strong fighting the animals on Mt. Corvo. It was how Rayleigh would have trained him if he got that far in his adventure.
Luffy just knew that the best way to learn was by doing things, so that was how he approached his training.
"You really thinking me kicking you is going to make you stronger?" Sanji asked skeptically after the whole time travel thing had been explained and his captain had told him what he needed.
The cook puffed on his cigarette for a long moment before replying. "Get the Marimo to do it. I need to make a treat for Nami-swan."
"She kissed me on the cheek two loops ago." Luffy revealed.
"You shitty rubber!" Sanji growled and launched a flurry of kicks at his captain.
The rubber man avoided them by bending like a piece of paper, using CP-9's Kami-E technique. He recalled using something similar against Enel's Mantra, before ever encountering CP-9. Now he was perfecting it. Soru was already mastered, although he didn't quite have the leg strength for it yet. Geppo was still a work in progress and so was Rankyaku. Tekkai he was having problems with because of his rubber body and Shigan he wasn't too interested in, although he still planned to learn it since the pigeon bastard mentioned that it was necessary in order to learn the Rokuogan.
The other technique that Lucci had shown him, the Seimei Kikan, Luffy realized he already knew. He used it to heal by eating meat.
This is too easy. Luffy realized that he wasn't getting anything out of this. Sanji at this point was just too weak and slow. That was why he closed his eyes and tried to dodge by instinct. Immediately, he started taking kicks to the face.
Haki, a mysterious power that let you fight Logia Devil Fruit users. Ace hadn't explained it very well and Luffy hadn't understood it. Robin had tried to facilitate that conversation, but in the end the only thing Luffy got from it was that it was a mysterious power that you gained from facing and overcoming challenges.
Kenbushoku Haki was the only one he had the slightest inkling of true understanding of. Enel had called it Mantra, but it was definitely the same power. Ace had confirmed it.
It was a power that let you sense people and what they would do, which sounded incredibly useful.
"Oi, what are you doing?" The cook stopped, his rage cooled thanks to getting a few kicks in.
"Boa Hancock, the Pirate Empress, the most beautiful woman in the world, fell in love with me in a day." Luffy said blandly. He'd gone through enough loops to have learned plenty of ways to motivate Sanji.
"DIE FOR YOUR SINS!" The cook roared and unleashed a furious barrage of kicks at his captain.
Luffy, with his eyes closed, failed to dodge most of it, but he refused to open them. This was the way to get stronger!
He still wasn't sure how he would train Busoshoku Haki, short of maybe having Zoro slice him up, and he was completely lost on Haoshoku. It wasn't like he didn't want to find difficult challenges to overcome, but this stupid time loop wouldn't let him do anything new!
What Luffy didn't know was that simply maintaining his will against the weight of time pressing down upon him was already gradually growing the strength of his spirit. It wasn't as big of a burst of growth as had come from the many hardships he had suffered in the first go, but it was a consistent and steady.
XXXXX
Of course, sparring would never be as effective as real combat, so Luffy made sure to use the enemies they encountered for training, not that they realized or appreciated it.
"Stand still, human!" Arlong screamed, punching, biting, nose-stabbing, slashing and throwing water like a madman.
Luffy paper-noodled his way through everything. Occasionally he would close his eyes and do it that way, but he didn't think that he was using Haki to dodge – Arlong was just too predictable to him.
Giving up on that, he poked the fishman in the chest with a finger. "Shigan!"
"What was that supposed to be?!" Arlong snapped, uninjured. Luffy's finger had bent instead of piercing through him.
Luffy gave it a sour look, still dodging return attacks. He had a feeling that he needed to train up his fingers to be able to do that, training which he lost every time he came back.
Trying something different, he lashed out with his leg, so fast that there was a whipcrack sound at the point of his toes. A blade of air took Arlong across the chest, but instead of cutting him open it left only a welt.
"You are too weak, too weak to hurt one of the superior fishman race." Arlong gloated. "All you can do is run away, like all humans!"
"My crew kicked your crew's ass." Luffy pointed out.
In fact, Sanji had been practicing the Rankyaku on Kuroobi. He was already better at it than Luffy, thanks to his leg focused fighting style.
"I will kill them for that after I kill you!" Arlong spat.
"Uh huh." Luffy couldn't even be bothered. "Tekkai!"
All the watchers were baffled as the previously untouchable rubber man suddenly stopped dodging and allowed himself to get wailed on.
"Luffy, what are you doing?!" Nami screeched, both angry and afraid.
"Oi, is this really the time to be training?" Sanji questioned, with Usopp nodding in agreement.
"It's always a good time for training." Zoro weighed in from the ground, in a great deal of pain from the injury Mihawk gave him.
Arlong froze, hearing this comments. "Training? You are using me for… training?"
Luffy shrugged. "What else are you good for?"
Curiously, this did not make the fishman calm down.
XXXXX
"WHAAAAT?!" The Marine officer in charge of assigning bounties bellowed into the Den Den Mushi. "Repeat yourself, Captain Nezumi!"
The corrupt and beaten up captain on the other end dutifully did as he was ordered and described the techniques that one Monkey D. Luffy had been using against Arlong.
"This is a disaster." Lieutenant Commander Brannew moaned.
As part of his duties, he was rather more 'in the loop' than someone of his rank would normally be. As such, he could recognize the Rokushiki when it was described to him.
And now some rookie pirate was showing a worrying amount of knowledge and mastery of the Marines' secret martial art? Completely unacceptable!
XXXXX
"GAAAAARP!" Fleet Admiral Sengoku roared at his old friend. "WHAT'S THIS I HEAR ABOUT YOUR GRANDSON KNOWING THE ROKUSHIKI?!"
"Eh?" Garp grunted in confusion. "Where did he learn that?"
"YES, GARP. WHERE DID HE LEARN THAT?" Sengoku's volume still hadn't gone down.
"Wait, you think I taught it to him?!" Garp was shocked!
"Who else could or would have?!"
"Don't know."
"DON'T JUST SHRUG IT OFF!"
XXXXX
"What the hell is this?!" Nami screeched, holding up a bounty poster. "Straw Hat, Monkey D. Luffy, sixty million beli?! Why is it so high?!"
"Ooooh, it went up!" Luffy grinned happily. That was double his previous starting bounty!
"Don't be happy about it!" Nami clobbered him. "And why are you being accused of stealing Marine secrets?"
Normally, pirates were simply accused of a bunch of generic crimes like raiding and pillaging, whether they actually did them or not. Stealing Marine secrets stuck out like a sore thumb.
"Oh right, that Rokushiki stuff." Luffy nodded in understanding. "The Marines don't like it when pirates figure out their techniques."
"They're doing it wrong anyway." Zoro grunted. "Why would you launch air blades with your legs when you could do it with swords?"
"Are you picking a fight with me, Marimo?!" Sanji roared.
"Bring it if you've got the guts, Ero Cook." The swordsman scoffed.
"None of you are taking this seriously at all." Nami despaired.
Usopp patted her on the back sympathetically.
XXXXX
Captain Smoker usually didn't bother looking at a pirate's bounty poster. Usually, the bounties in the East Blue were small and so far below his strength that there was no point. No ship that flew the skull and crossbones when sailing into Loguetown ever sailed out of it.
For a sixty million bounty, which HQ had called him to make absolutely sure that he caught? Yes, that one he looked at.
This created some problems for the Straw Hats.
XXXXX
"How are we supposed to resupply with the Marines in our faces like this?" Nami screeched in frustration.
"We just have to beat them up." Luffy shrugged. He wasn't sure why Smokey was so much more aggressive than normal, but it didn't really matter.
"You're getting ahead of yourself, Straw Hat." Smoker growled, having prepared an ambush at the docks.
"I didn't even get a chance to find my two new swords." Zoro scowled. Luffy had told them about the time travel this loop, so he knew that he would get them in Loguetown, but it would be hard to do with the Marines in the way.
"That white hilt!" A female voice exclaimed with a gasp. "The Wado Ichimonji, one of the 21 Great Grade swords. And in the hands of an evil pirate…!"
"K-Kuina?!" Zoro spluttered in shock as the woman stepped forward, her face a dead ringer for his lost friend.
"My name is Master Chief Petty Officer Tashigi." She said sharply, glaring at him. "And your sword will be confiscated!"
That snapped Zoro out of his shock and he glared back. "You'll have to kill me first."
"Don't glare at a lady like that, Marimo!" Sanji interjected angrily.
"Mind your own business, Love Cook." Zoro snapped back.
"All beautiful ladies are my business!"
"Oi, don't we have more important things to be worrying about right now?" Usopp asked in a dull deadpan, knowing that he was wasting his breath.
"Is this crew really worth sixty million?" Smoker wondered, a vein throbbing on his forehead as he saw that none of the pirates were taking them seriously.
Well, the orange-haired girl was, but even she looked more annoyed at the fact that they wouldn't be able to get their shopping done in peace.
"Enough, I'm taking you all in." He declared.
"You sure you want to try that, Smokey?" Luffy asked, picking his nose casually. "I'll kick your ass."
"We'll see about that." The Marine Captain said grimly, counting on his Logia invincibility.
XXXXX
They did see about that. From the ground, where they lay after getting the stuffing kicked out of them. Smoker cursed to himself for carrying his own undoing with him and letting the pirate take it. Because of that, he had to watch as the Straw Hat Pirates had free reign of Loguetown while the Marine garrison lay defeated.
It was a horrible humiliation, but not the disaster it could have been. For all his fears, the Straw Hats didn't pillage the town for all it was worth. Instead they just… went about their shopping. Sure, the captain yelled about how he would be the Pirate King for all to hear and the conviction in his voice was terrifying, but they didn't hurt anyone.
Smoker then realized what kind of pirates he was dealing with. In many ways the most dangerous kind.
XXXXX
"Robin! Robin, I know you're here!" Luffy bellowed into the air of Whiskey Peak. "Robiiiiin!"
"I don't think your friend is here, Luffy." Vivi said awkwardly.
"But she's always here." He complained.
Robin was, in fact, present, but she simply refused to show herself. After seeing the Straw Hat Pirates demonstrate the Rokushiki, she had come to suspect that they were part of Cipher Pol and would not risk a meeting.
That their captain apparently knew she was here, even if he couldn't find her, was even more worrying.
XXXXX
"Cipher Pol, hmmm?" Crocodile pondered after Miss All Sunday reported to him of the supposed 'pirate' crew that Princess Vivi had joined up with. "Awfully careless with their techniques if that was the case."
"True." Robin conceded. "But I can't think of any reason for a rookie pirate crew to know those techniques. Monkey D. Luffy might be Garp's grandson, but even the Hero of the Marines couldn't get away with teaching the Rokushiki to a pirate."
"He hasn't been to the East Blue in years anyway, prior to his recent visit." Crocodile dismissed. When you were running a secret criminal syndicate, it paid to keep track of dangerous enemies.
"Whatever the case, they are going to be trouble." She pointed out.
Crocodile grunted in agreement. "Pull our agents out of their path. Pirates or government agents, the desert doesn't care."
XXXXX
"So that's what the stealing Marine secrets thing was about. I was wondering." Ace shook his head.
"You're just accepting the time travel story?" Usopp asked incredulously. It had taken him quite some convincing to accept it.
"I know my brother and he's a shitty liar." The veteran pirate snorted. "Besides, there's no way a weakling like him could have gotten a bounty that big right from the start."
"I'll kick your ass, Ace!" Luffy hollered, offended.
"Even time travel won't be enough for that." Ace continued to tease.
"Wait, I need you to explain Haki to me again!" Luffy remembered.
"Huh, I told you about that, too?"
"Yeah, but you suck at explaining it. Even with Robin helping out, I couldn't understand what you were saying."
"You suck at understanding it, Luffy!" This time it was Ace who was offended.
XXXXX
Crocodile could not afford to be seen fighting government agents, even undercover ones. He also couldn't allow them to snoop about his operations.
It was a conundrum, but he had a solution.
As soon as the Straw Hats left the safety of the coastal cities, they were battered by sandstorms. Endless, relentless sandstorms. It didn't matter how strong they were or who they worked for, the sandstorms allowed them no respite. They couldn't go forward or back, forced to take shelter where they could.
But they didn't have an infinite supply of food or water. Eventually they ran out and died of dehydration, just another set of victims taken by the desert.
It wasn't a strategy Crocodile would usually think to employ, not least of which because it required him to put everything else on hold while he used his Devil Fruit for several days in a row. But as a secret means of long distance attack it worked beautifully. If the Straw Hats were Cipher Pol agents, then nobody could ever prove it was him who had killed them.
XXXXX
Luffy took a deep breath of fresh, unsandy air on his dinghy. Then he got mad.
"That damn sand croc! He didn't even fight me this time!"