Summary: Wohoo, we finally learn what Devil Fruit Luffy was after...and get a critical revelation about them that is one of the biggest changes I'm making to canon...
Chapter 9: Hunting
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Nearly a year and a half had come and gone since his first trip away from Dawn Island. Luff had repeated that trip twice since then, gaining more skill with his sword and connecting more thoroughly with Kuina and Zoro. To his own legitimate surprise, both of them had managed to unlock a single form of Haki, Observation for Kuina and Armament for Zoro, though neither could do much with it yet. He had also taken two other journeys, hitting various other islands around the East Blue, mostly without finding what he was looking for. Which wasn't to say he'd found nothing. He'd made an excellent series of contacts on the Organ Isles, which had provided him with supplies to build a proper workshop near his hidden little cove on Dawn Island. Said workshop was now well equipped for small scale smithing, particularly for working with Guns and Swords.
It also had some slightly larger equipment which he was using to experiment with materials for ship building. Luffy somehow doubted he was going to get his hands on Adam Wood in the East Blue, and he wasn't content to build a ship that would need replacing halfway through their journey. If that needed to happen, then so be it. But he refused to plan for that eventuality. Given the butterfly effects he'd already witnessed fully at work with Kuina, he wasn't at all ready to assume they'd even stop at Water Seven. Best he build the best ship he could from the start, which meant something better than a standard wooden hull for his final catamaran design. Thankfully, it was something the System Store was able to help with, providing books on various materials and alloys that he suspected had been known at some point in this world, but had been lost. Lunarian Steel didn't exactly sound like a normal metal, after all. So far, he'd failed to reproduce that particular alloy, though he had managed a small amount of Wootz Steel. Which he quickly recognized from Alex's memories as being roughly the same as Damascus Steel from Earth, at least in appearance. In properties, he had no idea, not having ever looked into ancient metals like that.
He had, on those exploratory trips, struck out on the other things he was looking for. Despite keeping his ear to the ground for word of a Cat-Burglar targeting pirates, he'd yet to hear word of Nami. He also wasn't nearly crazy enough to go near the Conomi Islands just yet. He had zero delusions about how well he'd do against Arlong and his crew, as much as he desperately wanted to help Nami. Likewise, as with Nami, so with Devil Fruits. Despite hitting up a half dozen islands, he'd yet to get a location for even one, which was beginning to irritate him. He should have expected it, probably, but that didn't make it any less frustrating.
Ironically, it was on his first trip of a new year, where he'd been intending to simply visit the Dojo again, that he finally got lucky on the Devil Fruit front, at least. His Weather Sense ability had warned him of an unexpectedly large stormfront, and he'd not been eager to test his sailing skills against that sort of thing just yet. He'd put in at a small uninhabited island, intent on waiting the storm out, only for his routine check of his Spirit Fruit Locator to turn up a hit for the first time. He'd had to wait the storm out anyway, which had made him far more anxious than he'd have liked to admit. But then, when the storm cleared, the locator had led him straight to a Devil Fruit. One that made him groan…and hesitate. For multiple reasons.
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The Smooth-Smooth Fruit
Type: Paramecia
Characteristics: The Smooth-Smooth Fruit is a highly defensive Paramecia type, intended to teach a student of the Lunarian Academy of Natural Forces how to slip through reality untouched by it. Anything the wielder of this Fruit does not wish to be touched by will slip off of them.
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Luffy reread that short observation multiple times. The…Lunarian Academy of Elemental Powers? What? Just…what? Was that what all Devil Fruits were?! The remnants of an old kingdom's schooling? How? What? Why? A quick examination of his System Store showed something he'd noted early on, but not thought much of. Nowhere did the term 'Devil Fruit' actually appear. They were, without exception, referred to as 'Spirit Fruits.' He'd written that off as simply a translation thing, or perhaps their original name before superstition had taken hold. Now, however, he had to wonder if he shouldn't have made the connection to other things, like Haki, instead. Were Devil Fruits just…a training tool?
It had taken him long, long minutes, closer to a quarter of an hour really, to finally force his mind to stop working through the implications of that possibility. When he'd managed to halt his racing thoughts, he'd instead been forced to confront another issue. While this Fruit being here made a painful amount of sense, given that Luffy couldn't have launched Alvida that far with his East Blue strength, this specific fruit was also potentially useful on its own. Not for Luffy, of course. It didn't offer the late-game power he was looking for. It would, however, be a near perfect Fruit for someone like Nami, who wasn't really a front-line combatant. Sighing, he plopped down and wrestled with what to do. Get his own Devil Fruit now? Or potentially strengthen his crew later?
Worrying at his lower lip, he though it through for perhaps another half an hour, working through it from every angle he could. Detailing every pro and con. Then, with only the barest hesitation…he opened his System Store and shoved the Fruit at it. As he'd hoped, it immediately offered to buy it in exchange for a single Spirit Fruit Coupon, and he mentally clicked yes. In the end, he had zero guarantee he could even recruit Nami, let alone that she would want a Devil Fruit. Besides, if he died for lack of power against some early enemy, it wouldn't matter much if he'd 'held onto all the health potions for an emergency.' Despite the System, this world wasn't a Game, and letting gamer habits of storing everything for some nebulous point in the future where 'you might need it,' wasn't going to do him any favors.
He spent another minute buying the Fruit he'd been eyeing for years, unwilling to risk it being found by someone else as some last-minute trick of fate...but then he promptly stored it in his inventory. Eating a new 'Spirit Fruit' while on a tiny island all alone, with the intention of spending a week sailing two directions over open water that would suddenly be a seriously threat to him, would be stupid. Besides, the moment he'd bought the Fruit, the spot it had been in on the System Store lit up with another item. Mentally tapping the icon of a book, his earlier thoughts were forced to the front again.
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Lunarian Academy of Natural Forces: Guide to Mastery of your Spirit Fruit! – 750 Shop Points!
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Oh for fucks sake. He was not looking forward to whatever world-shattering bullshit was in that. Which did not prevent him from prompting spending the shop points on it and storing it, too, in his inventory. Likely to be migraine inducing or not, he wasn't going to be consuming his Fruit until he'd read that thing Cover-to-Cover…
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Luffy closed the Guidebook with a snap, then promptly faceplanted on the desk of his workshop. He had, in fact, read the entire book Cover-to-Cover. It was a rather thick book, which is why he was only finishing it now, two weeks after returning to Dawn Island. The entire thing had been as enlightening as utterly frustrating. It had been clear from the start that the Guide presumed you had a lot of knowledge that Luffy lacked. Parts of it were so highly technical that, despite reading those bits multiple times, he couldn't make heads or tales of them. Yet, despite that, he'd still managed to work out several bits of important theory, as well as some critical practical knowledge he was pretty sure every Devil Spirit Fruit user on the planet would cheerfully murder an entire island of adorable baby seals for. Groaning into the workbench, he did his best to organize what he'd discovered.
Point one. Spirit Fruits were, in fact, creations of some ancient group. There were a few references in the Guide that made him think it wasn't actually the Lunarians, but the Lunarians had at least understood what they were enough to properly use the things.
Point two. They really were training tools. They had apparently been created as a short cut to learning how to use Spiritual Energy to manipulate reality. A fair bit of the text on that topic matched what little Luffy knew about Haki, leaving him to theorize that Haki use had once been far more advanced. That, instead of there only being three types, those three types were actually just the first rung of a much more complex discipline. One that had allowed for the sorts of things Spirit Fruits could do, if you developed your spiritual potential the right way.
Point three. Related to the previous point, Spirit Fruits were essentially the permanently concentrated knowledge of someone who had mastered the specific manipulation of Spiritual Energy that allowed them to do whatever fuckery the Fruit was for. Which left him with serious questions about what sort of drugs some of those ancient masters of Spiritual Energy had been on, to create some of the weirder Fruits out there.
Point four. Consuming a Fruit gave an instinctive ability to use your own Spirit Energy the way its creating master had figured out. That instant, instinctive grasp was just that, however, instinct. It was originally intended to be used by a student as a training tool to achieve conscious mastery of that method of Spirit Manipulation. At which point, they would no longer need the Fruit and it could actually be willed to reform into a Fruit for a new student to use.
Point five. The most practical point of all. There were levels of mastery to using the Fruits. This, in point of fact, was the unknown factor that caused significantly different levels of reaction to things like seastone and sea water by Fruit users. There was a price to be paid, a tradeoff, for having a leg up via a Fruit. While using one, your Spiritual energy was out of balance, creating an elemental weakness. Technically, Fruits could have been made with different weaknesses, but there were no oceans on the moon. Which made it completely logical that the Lunarian Fruits which likely made up all known 'Devil' Fruits had gone with a weakness to the spiritual essence of the sea. They weren't likely to run into it, ergo it was a perfectly safe and logical choice. As you mastered a Devil Fruit, your Spirit got closer and closer to properly aligned, and the weaknesses affected you less. Someone who had gained near total conscious mastery of their Spirit Fruit could, in fact, probably actually swim. Someone who had reached the point of being able to 'eject' the Fruit while keeping the power? That person would no longer suffer the weakness at all.
That little detail almost certainly explained why some people were able to power through, at least a bit, when in contact with seastone or water. Those individuals were likely the ones that had experimented the most with conscious use of their Fruit, unknowingly following the path that they were supposed to be training tools for. That was big, since the Guide had included steps and methods intended to help train control of a Fruit. The process was supposed to take years, even with access to a lot of stuff Luffy didn't have and couldn't even recognize from the descriptions in the books. Without that access, it might not even be possible to gain true mastery. But…even partial mastery, the ability to at least somewhat react while in water or touching seastone? That was potentially priceless. Particularly if no one suspected you could do it.
Luffy sighed and took out his Fruit. Garp was due back soon and Luffy had considered waiting until he had come and gone again, concealing the Fruit from him. The truth was, however, that while Garp might not have a Fruit himself, he doubtless knew a lot about both their good and bad sides. If anyone could help him through any initial downsides, and had the motivation to do so, it was his gramps. Even if Garp's methods were likely to be unpleasant. No, better to do this now, and trust that Garp was unlikely to speak about it to anyone for fear of drawing too much attention to Luffy too soon. Knowing it was supposed to taste awful (to humans, apparently they actually tasted good to Lunarians, which was irritating to discover), Luffy delayed for a last moment by using Observe on the Fruit.
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Spirit Fruit: Model Raijū
Type: Mythical Zoan
Characteristics: The Model Raijū Fruit is a combination Fruit of immense power, combing the ability to channel, create, and turn into lighting and thunder, with the ability to shape shift into various animal forms colored after that lightning. This is a highly prized Fruit and only given to the most prestigious and promising students of the Lunarian Academy of Natural Forces, due to its high versatility. The user will learn to manipulate and become the elements of lighting and sound, as well as shape shift into various increasingly complex forms.
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Of all the Fruits Luffy had read the descriptions of…this one was the one that had called to him the most. He'd always found the power of thunderstorms enthralling, he understood the power of electricity all too well…and the ability to shapeshift into a bunch of animals was just fucking cool. The fact that it was a Fruit that would stand up well to some of his most dangerous possible opponents had honestly only been icing on a very delicious looking cake. Now, if only this was going to taste like cake.
Having stalled quite long enough, Luffy closed his eyes and took a big bite out of the Fruit. He instantly gagged, wanting to spit out the utterly foul taste that made his eyes water, yet feeling strangely compelled. It was, he realized, as if his very Spirit was insisting he swallow. Eyes popping open in the realization that it was probably a safety feature after someone started initiating the process to fuck around with own Spiritual Energy, Luffy chewed quickly and forced the Fruit down. Thankfully, there was no compulsion to eat the remainder, and the Guide had said doing so was completely unnecessary. Indeed, even as he watched, the Fruit was simply turning to dust in his hand.
For long moments, Luffy waited for something to happen. Then, just as he was thinking there wasn't going to be any sort of noticeable effect, his eyes rolled up in the back of his head and he passed out. As he slept, he dreamt of a roiling storm and many creatures joyfully basking in it…
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Status
Name: Monkey D. Luffy
Age: 12
Level: 24
Spirit Fruit: Mythical Zoan - Model Raijū
Money: 4,761,000 Belli
Shop Points: 11,550
Perk Points: 7
Spirit Coupons: 0
Stats:
Strength: 54
Dexterity: 59
Endurance: 65
Intelligence: 59
Wisdom: 47
Charisma: 46
Luck: 51
Free Stat Points: 145
Perks
Gamer's Body: Grants a body that allows for the user to live the real world like a game. Wounds healed on rest. Status Effects removed on Rest.
Gamer's Mind: Allows the user to calmly and logically think things through. Gamer can suppress negative emotions at will.
The Will of D: Bearer holds the inherited will of the Family of D. Effect: Live in Interesting Times, ?, ?
Outsider's Perspective: Imported save data increases relevant stats, as well as relevant skills when acquired.
Danger Sense: A combination of Haki and gut instinct for trouble lets you sense dangers to you and others near you. Whether or not you can do anything about them is up to your skills.
Designer (General): You're exceptionally talented at more than one field of design! You have an intuitive sense of how best to optimize designs you've come up with!
Empathy: Beyond merely your Haki, you have a very good idea what the people around you are feeling. You're nearly impossible to lie to and everyone finds you easier to open up to.
Gifted Hands: You are naturally good with your hands. Anything from art to martial arts gets a helping hand. Your instincts for all such things are 10% better than they should be, and you get a 5% boost to XP gain for any skill based around working with your hands.
Gun Nut: Despite your age, you've managed to learn a lot about guns! How to clean them, how to make them, and even a little bit about how to shoot them! Gain instinctive knowledge of any gun you handle, as well as 10% faster XP gain for the Gunsmith and Gunslinger skills.
Haki Expert: Having proven talented with all three forms of Haki at a young age, you are 20% better at wielding it and 10% better at teaching it.
Intuitive Combatant: You are naturally gifted at learning combat. You are 15% faster at learning any type of combat, from the use of guns to punching lights out with your bare fists!
Training Expert 3: Get the most out of training! Not just for yourself, but for your crew too! Gain instinctive knowledge of the best ways to tweak your training for those GAINS BRO! +35% XP for Training your own skills, or for Training others in skills in which you outrank your trainee by at least 10 points.
Sage's Curve: You learn intellectual pursuits much faster than normal, and retain the knowledge more completely. You have a 20% boost to learning speed and memory retention of any intelligence or wisdom-based skills.
Sword Enthusiast: Despite your age, you've managed to learn a lot about swords! How to clean them, how care for them, and how to identify them! Gain instinctive knowledge of any sword you handle, as well as 10% faster XP gain for the Blacksmith(Sword) and Swordsmanship skills.
Sword Savant: You have created a new sword style at an incredibly young age. Know its flaws and how to fix them instinctively.
Quick Shot: You have incredible accuracy with firearms while on the move. +100% natural aim while firing without sights.
Weather Sense (Intermediate): You can predict normal weather with considerably accuracy, everywhere but the Grand Line.
Bonus(Dex): Ambidextrous! Through hard effort, you've become genuinely ambidextrous. Provides a major bonus to attempts to dual wield, the ability to pat your head and rub your belly at the same time, and more!
Bonus(Endurance): Damage Mitigation. You've toughened up to the point that 15% of all physical damage dealt to you is mitigated outright.
Bonus(Intelligence): Accelerated Thought. During moments of intense effort or danger, you can think much faster than a normal person, allowing you to break through blocks in your workflow or create desperate plans on the fly!
Bonus(Strength): Power Strike. You've gained the ability to focus all your strength to a fine point, doing far more damage with your hits than you ought to, though only in short bursts.
Bonus(Luck): Fortune's Favor. Lady Luck likes you, in any situation involving luck, you can feel what the results will be, as if dice were tumbling in your head. Is it truly chance if they fall more often in your favor than not?
Skills
Brawling: 49
Blacksmithing: 21
Carpentry(Ships): 52
Gunslinger: 31
Gun Smithing: 33
Haki(Conquerors): 15
Haki(Observation): 62
Haki(Armament): 38
Knowledge (World History): 31
Knowledge (Navigation): 35
Medicine: 24
Meditation: 65
Observe: 71
Free Running: 42
Sailing: 45
Sciences: 43
Slight of Hand: 27
Sneak: 43
Sword Mastery(Wave Dancer Style): 57
Spear Mastery: 20
Staff Mastery: 28
More…
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A/N 1: So...yeah...there has never been an official explanation for what Devil Fruits actually are. Given Luffy has a System, it made sense that he'd get some information on that topic. Moreover, it allowed me to unify the bullshit of various One Piece 'magic' elements into a cohesive whole. There are also plenty of bizarre ancient civilizations that were CLEARLY more advanced to attribute this sort of thing to in One Piece. If you dig into it, One Piece has everything from giant robots to SPACE Pirates fully established in its past. The Devil Fruits (or Spirit Fruits) being a remnant of one of those civilizations fits well enough, and allows me to weave them into a more cohesive/unified understanding of how the more 'magic' type powers of One Piece work. Also, no, Luffy isn't going to instantly master his fruit and be able to swim. By the time he sets sail fully at 17, he'll be less-than-completely-helpless when touching seastone or in water. But he'll still be immensely weakened by either. This is intended to be something he won't fully be able to get a handle on until he's reached the New World, and possibly not even then.
A/N 2: Luffy's Devil Fruit choice. Mythical Zoan's are pretty much bullshit, allowing multiple powers from the same Fruit. Given a System Shop that let him pick anything that wasn't currently in use? You bet your ass Luffy was always going to go for one! I spent several hours, early on, working my way through several dozen possible Mythical Creatures that he could be a Zoan of. Two of my favorites, the Pheonix and Kitsune, are sadly already in use in One-Piece, by characters that would have already had their Fruits before Luffy got his system. After a lot of debate, I settled on the Raijin since it ticked several boxes. A powerful element, some shapeshifting ability, and a high power-ceiling if used right. I was a little reluctant, given that there are several stories out there that give Luffy Enel's Lighting Logia fruit, which is functionally going to often be similar to how Luffy uses it most of the time. In the end, though, there weren't any others that I felt hit all the right notes without also running into a similar issue. Giving him a Dragon fruit of some sort, for example, would have just created comparisons between him and Kaido. A few others were female-only myths which would have been a complication. And so on. So, Raijin it is!
Patreon
Question: Is the devil fruit buy a one time thing or can he get more? To go along with that question can he give the fruits bought by the system to other people?
If there isn't a limit and he can keep on buying, then there isn't anything stopping him from just buying Nami a better fruit in the future. There are a couple of trash devil fruits users in the future that he would know about because of the plot. He could just go after them with his plot of the story or go after bounties that are known devil fruit users in order to buy his team members better fruits.
He can absolutely buy more than one. Which is part of the reason he ultimately chose the way he did. There aren't all the many Fruits in the East Blue, and he can't buy a fruit already in use. Hence the hesitation at giving up one that really is excellent for a backline or non-combat focused crewmember. But the ability to acquire something decent for those that want/need it in the long run was certainly something weighing in on the side of giving it up now and worrying about other fruits later, at least in the back of his mind.
@NovusPeregrine Alright just curious. He mentioned giving the slippery one to Nami and to be honest I thought he could give her a better one then that. The door door one would be good for stealing and hit/run tactics with guns/bombs. Heck even the soap one might not be too bad for her from Enes lobby.
For his fruit choice to honest I wasn't the biggest fan initially but it works for him. I myself was thinking either a high tier logia or a mythical zoan like you had him choose.
The three I have always been a big fan of were the lightening one, which like you said is overused, the venom one, and the shadow one for Moria(too many weaknesses though). Probably woudn't pick the later 2 though if I had a choice of better options.
@KidBuu699 Yeah, the Fruit choice was easily the one thing I've spent the longest time on (aside from the pairing, maybe!). I considered dozens of known Fruits that wouldn't have been in use yet...but didn't really think any of them fit. The venom and shadow ones, for example, were likely already with their current holders by the time he could have grabbed them. Even when I ultimately decided on a Mythical Zoan, I spent probably 3-5 hours doing through mythical creatures of various origins. I actually tried to avoid lightning...but all of the other ones I liked ended up being either already in use (Pheonix and Kitsune being two examples), or female only (which might have been a funny complication, but I decided against it). The final choice was just too good a fit to not use, particularly as I've gone to some effort to shift away from the way Enel uses his fruit. It will be seen more in the next Patreon release, which is coming out in two days, but Luffy uses the lightning aspect of his Fruit via physical contact far more than he does as ranged bolts. As well as for mobility. And he uses the shapeshifting aspect for mobility and utility, with occasional use for additional physical power.
@NovusPeregrine I think all three of the fruits I mentioned would have already had owners. If my memory is right all three of the owners gained the fruits when they were kids and they are all older then luffy. Not sure on Moria but he has been in the pirate game for a long time so I would assume he had the fruit to reach his level.
For mythical Zoan I think you picked the best option overall. You wanted a fruit to make him faster(dodging) and lightening based one is the best for that. Light based would have been alright but I'm not sure on legendary animals being light based. A wind or mist/illusion would have been alright but probably lackluster on the power scale/attacks. Fire would have fit as well but I agree with you on dragons being overused and phoenix is already taken. Fire would have gone well if he got the cursed holy sword as well. Might have been able to combine the two fire moves.
Now personally I wasn't too big on the shapeshifting aspect. My understanding was the fruit was a legendary dog/wolf based one and zoan fruits usually only keep the transformations of the animal that the fruit is of. I see the need on a flying based animal for his travel though. Perhaps some type of mythical thunder hawk. You see Thunder Rocs in a lot of xinxia stories but I don't see thunder being a part of their actually mythology.
For his lack of ranged thunder moves you could use the excuse that he is hiding his true fruit in the beginning. That he is trying to make people think he just has a zoan wolf/dog one in order to keep a low profile.
However, I will say that him having the ability to shoot lightening makes his off-hand gun seem kind of pointless. Still good for seastone bullets but thats about it. Why bother using/reloading a gun in a fight when you could just finger blast lightening at people.
@KidBuu699 Right. So, addressing the shapeshifting thing first. Because you're not the first person to ask about that. I gave it to him because while the Raiju myths SOMETIMES mention it as a dog or wolf...well...let me show you a snippet of the wikipedia entry:
"A raijū's body is composed of (or wrapped in) lightning and commonly conceived of as taking the form of a white-blue wolf or dog, among other such animal forms as a tanuki, leopard, fox, weasel, black or white panther, serow, ferret,[1] marten, tiger, cat,[1] bear, porcupine, tapir, bull, rat, dormouse, lemur, rabbit, squirrel (usually flying squirrel, tree squirrel or chipmunk), water buffalo, lynx, pangolin, boar, deer, beaver, badger,[1] mongoose, civet, monkey, rhinoceros, sea creature (usually a marine mammal such as a dolphin, orca, narwhal or seal, although it can also take form of a sea turtle, fish (usually a shark, deep sea fish, chimaera, ray, flatfish, barracuda, pufferfish, sea horse, swordfish, marlin or eel), mollusk, echinoderm (usually a sea urchin or starfish) or crustacean, most commonly crab), amphibian (usually a frog, toad or salamander), insect (most commonly caterpillar, waterstrider, waterbug, grub, stick bug, cicada, praying mantis, wasp, hornet, dragonfly or stag beetle), worm, arachnid, millipede, centipede, komainu, qilin or dragon. It may also fly about as a ball of lightning (in fact, the creature may be an attempt to explain the phenomenon of lightning, such as ball lightning). Its cry sounds like thunder."
You see? I saw that insane list and went...'yeah, the most likely explanation is that it's a shapeshifter.' Doubly so since it's from Japanese mythology where shapeshifting is common in creatures. The Kitsune just being one of several examples. In fact, the Kitsune fruit in One Piece allows exactly that. And other Mythical Zoans are shown to provide multiple powers, so long as they are associated with the creature in question. Macro has full fire powers when transformed fully, can create it's blue flames even without doing so, and those flames can both harm AND heal. Both himself and others. His full transformation makes him intangible like a Logia...yet he's also shown to be able to form physical bird-like talons. (I used him and his fruit as the guide to structuring Luffy's, if that isn't obvious!).
Random note...I did consider the ThunderBird, actually. It made the final short list. But the shapeshifter aspect I could apply to the Raiju made it more interesting.
So the lack of thunder moves and the gun are actually related. Both of them are, more than anything, related to the fact that he's currently concealing what his Devil Fruit is. And will be trying to keep the WG guessing about that for as long as possible. He also initially conceived the fighting style prior to deciding on a Fruit, and the fact that he was already developing a style that would work well with being able to 'shoot' things with his off-hand was only an additional bonus. That said, the gun is eventually going to go through some upgrades to keep it actually useful...but yes, once his Fruit is out in the open, he'll often switch between the gun and lightning, depending on the situation. If fighting a DF user, having the ability to fire seastone bullets at them might make him use the gun, for example. And he'll get other special ordinance for it in time. So, in the long run, it will depend a lot on who he's fighting.
@NovusPeregrine So two things. First with the hiding his real fruit from the world government. I would suggest that in actual combat or where people are watching him that you pick one animal and keep with it. If he turns into multiple ones that will be a bigger attention maker that says "my fruit isn't normal."
Moving on to the gun/lightening/combat. So you could always combine the gun with lightening. Perhaps make a revolver upgrade that holds his lightening in the chambers as lightening. Could say that his lightening abilities are not as strong as Enel's fruit, and his lightening gets weaker the farther it gets away from him. Or just that the gun makes the range moves stronger.
Only other thing I would say on the gun is having multiple loaded ones in his inventory. Probably be easier to just switch between loaded ones in his inventory instead of reloading. Well unless you go with lightening bullets, then you just need a seastone gun loaded.
@KidBuu699 He's actually going to try hiding the shapeshifting animal thing entirely as long as he can. Can't be a mythical Zoan if he doesn't seem to be a Zoan, right? And, with keeping all of his lightning use in close...essentially, he's trying to set it up to look like he's an unknown Paramecia type when his fruit is seen (at first). Something like "control of static electricity." A fruit that wouldn't really worry the WG, until he's forced to use it more seriously in front of someone willing to report it.
His Inventory (and the System in general) is something he's NEVER intending to let anyone other than his crew discover. EVER. It's not a DF power, or Haki, so someone seeing it without having those as an excuse would cause EVERY red flag to go up and get him hunted down by people he can't handle, in numbers that would be scary. Even above the actual DF and his possession of Haki, that is a secret he will brutally murder everyone that sees it to keep. Short of a child or something. Not even Garp knows. As a result, only a truly desperate situation would make him pull something out/put something into it where an enemy could see.
Like I said, though, the gun will get some special ordinance :-p. Some of it will even exist fairly early. After all, his memories of Alex would have known that HE rounds were a thing. Aside from that...remember that things like dials and Usopp's pop greens exist in One Piece ;-). Even if it will be quite a while before they encounter them.
@NovusPeregrine Sounds good. Personally I would say to go the zoan path instead of the Paramecia type. With how weird Paramecia are I would think it would bring more questions then a zoan. Plus if he isn't using his lightening in combat, then it would be easier for him to just show his ability/movement. As long as no sparks come off of him, then a simple wolf transformation would explain his speed.
Now for the inventory system wasn't one of the points of his unique ship decision was that he did need a lot of cargo space because of the inventory system and he was going to use the inventory to make up for that? You mentioned that he would let his crew know about it but I think I remember you saying towards the beginning that he would have a bigger crew. More people equals more people to tell your secrets. More likely for someone to get caught and interrogated by the marines.
So what I am trying to get at is wouldn't the inventory be the thing he tells no one? If so he might have to rethink his final ship design to something with cargo/supply room to keep away the questions of where he is getting stuff.
@KidBuu699 The inventory thing...a bigger crew doesn't mean a BIG crew. He's only adding three additional people from the East Blue and maybe the same number from Paradise...and at least one of the original Straw Hats isn't going to end up with them at all. He's also going to be careful about who on the crew knowns. Essentially only telling either those that NEED to know (because they managed supplies) or that he completely trusts. So, no telling new crewmembers until he's certain of them. Possibly never telling certain members at all if he doesn't think they can keep it secret. By the time of canon start, it's likely a total of four people he's completely sure of will know. With his other two crewmates at that point likely still being in the dark. The Catamaran design also doesn't have NO cargo space, it just has less than a mono-hull of similar design. Given that it's going to be a bigger ship than the Going Merry, it would probably have a similar amount of native cargo space as the Merry. Which means it won't be hard to hide the fact they have more cargo than they technically have capacity for.
As for the DF. The problem with leaning on the Zoan aspect is twofold. One, it's weaker. There's a reason very few high-level pirates or marines have Zoan fruits (that I can remember at least), unless those are Ancient or Mythical Zoans. The second, more critical issue, though...is that not using the lightning at all would mean crippling his long-term fighting style. He isn't trying to hide his Fruit's nature FOREVER, just until he's already established/strong enough to give the powers that be pause in sending someone like Cipher Pol to deal with him early. He knows his lightning ability will be a fundamental part of his combat style. So spending years NOT using it in favor of developing an effective Zoan style would be...stupid. And being considered a Paramecia actually puts him in the generally weakest category. All fruit types of strong outliers (like Whitebeard's), but there's a reason Paramecia are considered the weakest/most random as a general category. A lot of the powers they provide are very limited, whereas Zoans provide a fairly universal stamina/strength boost, even for the less useful Zoans. Essentially, a Zoan is a 100% certainty of at least middling strength. Logia are a near 100% certainty of HIGH power. Paramecia...are a dice roll which tends to produce wildly mixed results, maybe of them not really all that good for combat. They are also the most common, so someone popping up with a useful Paramecia is just 'oh, he was mildly lucky that he got something decent.'
Essentially, the order of magnitude for his secrets goes like this. With the left being facts he cares the least about, to ones on the right which he'd most like to keep.
He Has a Devil Fruit->He's Garp's Grandson->He has a Strong Devil Fruit->He has Observation/Armament Haki->He is Dragon's son->He has Conqueror's Haki->he would like to brutally murder every Celestial Dragon on live Snail Broadcast->He has the System->He has outside context knowledge of their world.