Haunt 8: Shadow of an Emperor
-2 Years Later, Marineford, Fleet Admiral's Office
"Fleet Admiral!!!" An urgent man's voice cried out as a young man wearing a standard Marine uniform burst into the office of, officially, the most powerful man in the Marines.
"What is it seaman?" A large man wearing a pristine white, decorated Admiral's uniform with a a coat of JUSTICE draped on his shoulders questioned with a raised eyebrow behind his thick black-rimmed circular glasses.
And although in his late 50's, his grand Afro was still solid black, unlike most of his generation, with his prided mustache and burgeoning beard, matching it.
One of his few victories against his irritating best friend.
With a stern face accentuated by strong features, an aura of authority and strength cultivated over a lifetime of combat on the seas against pirates up to the level of the Pirate King himself.
This was the Fleet Admiral: Sengoku.
"The Whitebeard Pirates are on the move!" The marine informed him, earning a grave look from his top superior.
"Do we know to where?" Sengoku immediately questioned.
"Not with certainty, but we believe they are heading for... Fish-Man Island." The Seaman gulped nervously.
A tense silence hung in the air as Sengoku pondered over this information, debating on how to handle the matter.
He knew Whitebeard.
As longtime enemies, they both knew each other remarkably well.
So if the 'Strongest Man in the World' was moving to Fish-Man Island, it was likely for one reason: To Claim It.
As Fleet Admiral, he had heard of many changes occurring in the undersea Kingdom. Chief of which was the increase in bounties claimed by them and the ability to repel a great number of the scummiest pirates capable of reaching the fabled Island of Mermaids. This showcased a marked increase of strength they had not expected from a single Kingdom without Marine support due to reasons he despised.
He became a Marine to protect innocents, but was constantly forced to ignore those suffering the most because Celestial Dragons didn't want their precious supply of slaves to run out.
Relationships with the Ryugu Kingdom had been tense at best because Marines were unable to take responsibility for the pirate attacks which constantly occurred there due to said pirates usually fleeing from Marines into the New World the only way they could, from an Island with great Marine presence and near their Headquarters. It had always been a delicate diplomatic issue which past Marine diplomats, officials and even his predecessors struggled to keep in balance without the Celestial Dragons messing it all up and causing millions of naturally superior beings capable of breathing underwater to join forces in the New World against the Marines.
That would be a disaster unmatched beyond the Giants of Elbaf following suit.
So when tensions started to ease up somewhat as the Royal Family began organizing bounty claims and drop off, bringing captured slaves up for the Marines to send back home or at least organize safe returns, Sengoku and his old comrade, Tsuru, jumped on the opportunity to try and repair human-Merfolk relations at least somewhat.
It was difficult, especially with the 'sanctioned' Slave Houses selling some of their people right above them in Sabaody, but the new Queen had been spearheading the development alongside them to hopefully even bring their Island to the surface and join the world.
A grand dream, but a dangerous one for Fish-Men and especially Merfolk. Grand all the same, and Sengoku could respect the woman's fervor and passion.
But now, this would change.
Whitebeard moving personally meant he heard something that needed his participation, and Sengoku knew what it was.
Big Mom and Kaido.
News had reached him from their information gathering side regarding their growing interest or irritation towards the Fish-Man Island.
One of the major issues being that fewer pirates had been making it to the New World, limiting the number of new recruits to their expanding crews or to replace lost ones in their struggles against one another. Another being that, Fish-Men were ideal as soldiers or for any crew due to just how many natural advantages they had in combat and at sea. Kaido in particular would love to have them under his flag, while Big Mom's insane desires to 'unify' all races would push her to do the same.
Whitebeard making a move meant that he wasn't going to allow this. The man reportedly had close a relationship with the ruling king after all, and he wouldn't be someone Sengoku begrudgingly respected if he let his friends suffer under his rivals.
But, this in turn meant that relations with the Kingdom below the seas might take a hit on the fragile progress they had achieved due to them finally receiving protection, but under a pirate instead of the Marines.
A blow to their pride because Sengoku couldn't officially do anything of this scale without permission from above. Permission he knew he would not be given, especially if it meant clashing with the Whitebeard Pirates in a place like Fish-Man Island. They just didn't have anyone short of Garp and himself who could possibly match the monster, on top of not being able to bring the necessary Admirals and Vice-Admirals to take on the unknown numbers of Captains who would be joining that giant of a man.
So with a frustrated sigh, Sengoku did the only thing he really could.
"Send orders to nearby units to reinforce Sabaody. Whitebeard is likely moving to claim Fish-Man Island and I want to catch as many rats jumping ship." He ordered regally. "Tell Zephyr to move in as well. We'll need at least an Admiral on site in case some decide to go too far or if any Whitebeards come to this side of the Red Line."
"Y-yes sir!" The seaman saluted before quickly exiting the office.
"*Sigh* Now I have to tell the Elders." The Fleet Admiral reluctantly told himself as he picked up his transponder snail.
-Fish-Man District
Over the last two years, Fish-Man District had shown surprising growth in the face of danger.
Noah had slowly been turned into a veritable fortress by the Fish-Men and Merfolk, using Giant Bubbly Corals to allow for the great numbers of canons taken from Pirate Ships to function, also taking their time to reinforce the Ship of Promise after noticing that Sea Kings got rather irritable when it was damaged.
They had managed to organize mounted patrols, growing even closer to the sea creatures as bonds grew between riders and mounts, now having the common sight of young sea creatures swimming around the district or playing with similarly aged Fish-men and Merfolk.
For any Islanders, the sight of so many sea creatures living amongst them would be baffling, but here it was growing into a treasured practice.
Retired military officers or soldiers had also taken to helping others train with their weapons or body, trying to teach the skills they had learnt through training or experience, forming a militia. A place for teaching the young members of the community how to read, write, do calculation, learn history and geography was also formed by older women who wanted to contribute to the growth of the District as well, managing to round up the kids so they couldn't get in the way of adults while simultaneously reducing the risks of them being spotted or targeted by raiders as easy targets.
The only reason they hadn't completely shut themselves off from the Island proper was mostly because they still needed supplies and services they could only access from there, which had gotten easier with the amounts of pilfered treasure they continuously took from Pirates, it was honestly turning into Fish-Men looking forward to attempted raids sometimes, and due to one of the unofficial leaders of the District in their Boss's absence being an Islander.
That's right.
While Jinbe had grown to be incredibly respected in the District and the Island for his strength, honor, service in the military and to his fellow Fish-Men, Adam had also become someone many listened to.
The young hybrid was a shining star for the youths of the Island and District, with a reputation born of his monstrous strength and talent pushing him into the top fighting powers of Kingdom, and dedication towards actually helping others endearing him to many.
Unlike what Jinbe and Adam thought, many older Fish-Men and Merfolk from the District had actually figured out the fact that the young hybrid basically gifted them ways of growing stronger during the many months, talks over drinks tend to loosen tongues and allowed smarter and more experienced residents to piece together his subtle actions. But with how Adam never sought to take credit for the District's improvements or claim any sort of leadership role, many simply agreed to instead show quiet respect and support him while playing ignorant to his contributions beyond the obvious fighting he did.
Because Adam was a sign of hope to them.
Some would never admit it, but his very existence and every action helping them all, helped cement the fact that something good could come from humans and Fish-Men/Merfolk coming together. Even if quite a few knew about Tami's past and the general circumstances of the child's birth due to rumors and gossip spreading in regards to the local celebrity, it didn't change the fact that he was single-handily a sign of prosperity and a brighter future.
This actually resulted in the bitterest of Fish-Men, those who grew to hate too much, to also show fierce rejection of Adam, but they were simply too weak to even do anything to the monstrously strong child. They rejected many of the developments in the District as they simply desired to 'maintain their ways of life', some actually moving away from the District because it was 'becoming too much like the Kingdom that abandoned them to the mercies of humans.'
On the flip side, many also did join the Dojo or army, depending on which side of the coin they were on, to get stronger. Some even did their best to get jobs/apprenticeships on the Island to return with skills to better the District.
Another 'Suggestion' from the growing Fish-Boy that had been taken to heart. After all, they wanted better lives for themselves and those who would come after them, so why wait for others to do it for them when they've proven to themselves that they could?
This, of course, made many Islanders rather worried in regards to the sudden influx of District dwellers. They weren't used to so many of the 'rougher' people being around them, kind of like if a bunch of obviously gangster looking men suddenly started working in flower shops, retirement homes and in kindergartens.
Queen Otohime on the other hand, well she went full steam ahead with the idea.
Jumping aboard the 'District Development' ship without hesitation as she advocated for the Island to finally do what it should have always been doing: helping its citizen, even those outside their bubble.
Adam had actually met the Goldfish Mermaid Queen after she had heard about him and decided to visit.
-1 Year Ago, Lion Acupuncture
An 8 year old Adam was taking one of his 'break days' learning more about the weather patterns and systems found throughout Paradise, as well as how to use three-pointed Log Poses inside of it to better effect instead of limiting oneself to predetermined paths.
It was fascinating to him.
Plus having a calm day with Morgiana spending time at the café after finding a surprising hobby involving singing and music. The girl had an incredibly clear and powerful voice, with almost perfect pitch, so she was learning how to sing from the mermaids there in her free time.
Everyone was very supportive, especially Shyarly as she helped the Kuja girl, usually going to the café together.
And Harribel had actually been more interested learning how to cook after seeing Adam doing most of it on his own. The stoic girl was very considerate and wanted to help ease the burden by learning, accompanying the girls more as a guard when they went to 'work' so she could study more in the café's kitchen.
None of the workers minded the presence of the three.
Shyarly had long since been a regular presence, with her booth actually becoming an almost iconic part of the café at this point. Morgiana was bright and approachable, with a wonderful voice and upbeat energy, so she always caused guests to sing along to her shanties. And Harribel, who had been growing quite strong in her own right, served as a second coming of Adam when he wasn't there, cleaning out any trouble makers.
"ADAM!!! GET DOWN HERE PLEASE!!!" So when he heard his mother yelling rather oddly during his relaxation time, he grew curious.
He hadn't felt any kind of danger, just a few soldiers and a mermaid. Not really different from most days lately.
So coming down wearing an unbuttoned Hawaiian shirt with wave patterns and swim trunks matching them, his usual partner Soaring Sun at his hip as a subconscious act of never parting with one's blade, he found his mother stiffly sitting at her break table.
What surprised him was the person sitting across from him looking around at the medical charts, books, and supplies with interest.
Not caring about the two guards in royal uniforms, Adam focused on the obvious fact that the Queen was here.
Wearing a very long white kimono with a cream-colored carp-scale design along the hem and a sash around her shoulders that floated behind her head, being surprisingly tall for such a fragile woman, standing at 7'4" (224cm). Her face was more circular than most, but she was certainly attractive with her passionate green eyes, long golden blonde hair held up in loops by an orange hair ornament, and a slim figure.
"What's up mom? Why is her majesty here?" He asked curiously.
"A-Adam, Q-Queen Oto-Otohime said s-she wanted to m-met you." Was the strained, mechanical answer as Tami was internally freaking out over having the QUEEN OF FISH-MAN ISLAND IN HER CLINIC!!!
"Ok. But why? I don't remember doing much that has to do with the Royal Family." Adam wondered, not really caring too much about the woman's status.
He knew she was down to earth and caring, plus he himself didn't see Royalty as too big of a deal. He did respect the Ryugu Kingdom's Royal family because they were actually good rulers, with the clearest evidence being in how their children grew up, but he didn't consider most royalties to be anything important.
In fact, he had a pretty low opinion on most royals and nobles of this world.
And thanks to his growing strength, he could be confident enough in himself to not fear them.
"Oh but that just isn't true!" Happily exclaimed the Queen as she approached the mother-son duo, causing the former to stiffen nervously as she tried her best to flatten any of her spines against her body in fear of even nicking her. "You've been such a wonderful boy!"
Nearing Adam, the Queen joyfully cupped his checks and peppered him with grateful little kisses, leaving pink lip marks all over his cheeks and forehead.
"Working so hard to help people! Improving the District which so many simply wrote off even though they needed help the most! I couldn't just not come and thank you!!!" She very passionately explained, clearing quite a few questions about her presence.
"There's no need. The people of the District did most of the work themselves. Jinbe-senpai and I just have them the chance to do it." Adam humbly replied, feeling a bit embarrassed from the praise.
He's never been good with praise, preferring to do his work and moving on so people can enjoy and he could continue with following his desires.
"Nonsense! Even my big lug of a husband agreed that a remarkable child like yourself deserves a reward for all you did for the Kingdom!" Otohime happily revealed as Tami's eyes bulged out in true One Piece fashion at the mention that King Neptune not only knew of her son, but he thought he did so much good that he deserved a reward.
"What kind of reward?" Adam asked with interest.
He wasn't sure what the Royal Family had to offer considering even their 'National Treasure' was a double edge sword.
"That... we weren't exactly sure of." The Queen admitted before becoming upbeat again. "But that is why I'm here!
Better to hear about what you would want instead of getting it wrong by guessing!"
He could get behind that logic.
"A ship. If I can have anything... I'd want a ship that can help me challenge every sea in the world for when I'm old enough to do so." The young boy clearly told the Queen with a passionate fire she herself could feel with incredible strength and clarity thanks to her innate Haki.
"I was right." She softly replied as she fondly pat his wild but silky hair. "You do already have a dazzling dream driving you."
"I'm going to see everything the world has to offer!
To sail freely anywhere, no matter who tries to stop me!
Be it man or nature... I will beat them!" He told her as his Haki resounded fiercely with his declaration of freedom and the will behind it.
This brought Tami back to reality as she looked at her son with mixed emotions, always dreading the day he would go but also wanting to support him since she believed he could do it. He was her son, her pride and joy, her strong, kind and free boy who could do anything he set his mind to after all.
Queen Otohime on the other hand, she felt something else altogether, touching on the source of Adam's Conquerors Haki and witnessing a beginning swells this young boy in front of her would bring in his efforts to achieve his goals. She couldn't help but think of her own dream to allow Fish-Men and Merfolk to be under the same sun as humanity, allowing them to live like this young hybrid desired if they so wished.
It filled her with righteous determination!
"Yes! You desire a ship? I shall have the best shipwrights we can contact build one for you!" She declared with incredible certainty before storming out of the clinic with her guards urgently floating after her.
A few moments of surprised blinking later...
"Soooo... I'll take it as my request was accepted." Adam mostly told himself with a nod. "That takes one worry off of my mind."
"I can't believe the Queen was in my clinic." Tami mumbled on disbelief over what just happened.
-Flashback End
Adam still hadn't seen the ship itself as it was apparently going to be a surprise for later, but he had been asked about what kind of ship he would like and what he would want on board.
He decided on something around the size of the Thousand Sunny, choosing a Brigantine class since Adam wasn't planning on having a large crew. He preferred how Roger, Shanks and Luffy did things over Big Mom, Kaido, Shiki and even Whitebeard technically.
As for what he wanted onboard, beyond the standard stuff like proper storage, kitchen, sleeping quarters, sick bay and the likes, Adam also requested a large shower and bath, a study/small library area, various customizable rooms, training area, and some little luxuries for extra comforts.
He was going to leave the rest to the experts since he might know a lot about ships from his past life, but those had been moderns ones which only a few individuals in this world like an older Franky or Vegapunk could make a reality.
There was a notice regarding the fact that the ship would be given once he was old enough however, but Adam certainly wouldn't complain as new ships were expensive and this one was being gifted to him. He could admit that he was looking forward to that day however, having told them to create a ship with the name 'Eve' in mind.
But moving on from that, Adam had been quite pleased with his efforts over the last two years as a whole.
Beyond having grown to be 6'2" at the age of 9 and a half, his intense training and fighting have shown results which would make most men cry blood with envy.
Starting with his purely physical abilities.
Adam was officially a certified black belt in both Fish-Man Karate and Jujutsu, something which had been held off due to him constantly working on the martial arts while developing his own sword style. He just never took the test as belts never held much meaning to him either, preferring to continue along his path instead, but he chose to have himself be certified as Black Belt of the 100th level and as an instructor.
He had already been teaching Harribel and Morgiana on the side anyway, so might as well make things official.
Being able to easily use the techniques through surrounding water and the fluids in other people, successfully combining with Haki and having shown in-depth knowledge of techniques and philosophy had been enough after a show of prowess against various masters, Jinbe and the Grandmaster.
The latter of whom were still capable of defeating Adam, but it had been becoming increasingly difficult over the years as his titanic bodily might continued to grow thanks to innate strength, proper development and nutrition to support it, and the medicinal assistance to increase his gains further. A marvel of natural, artistic and supplemented efforts to craft a warrior of unparalleled potential.
Outside of Fish-Man martial arts, Adam had truly managed to gain full control of his body thanks to aid from his Master, Self Observation Haki and his anatomical knowledge. Gaining full control allowed him to perform the Seimei Kikan, even manipulating his shoulder blade length hair with greater dexterity each day and being able to further maximize the nutritional and medicinal benefits her could obtain.
Tekkai, and surprisingly Kami-e were almost side effects which came with having full control of himself. One relied on full muscular control to harden the body, mimicking steel in terms of durability, while the other required immense flexibility and fluidity to dodge attacks like a floating piece of paper, quite similarly to the concept of Shaori from Adam's past life.
A reason for these achievements stem from how Adam could 'see' his entire body inside out to understand what he was missing and how far he actually had to go, on top of his master's insane training to kept up with the mind breaking student.
Thanks to this development, Adam had actually succeeded in achieving a state where he could get 100% out of his physical abilities. An incredible feat for one so young.
But thanks to achieving the firmest base he could imagine, Adam had finally begun to devote himself fully to the sword, only deviating slightly to develop the remaining Rokushiki techniques since they were useful and would be integrated into his style.
Soru was a wonderful base for movement skills alongside Geppo, Rankyaku was already mastered a long time ago, Shigan was simple enough thanks to his strength and body mastery, allowing for very dangerous pokes when Adam used his knowledge of acupuncture, but he was still working on Rokuogan with the goal of turning it into a one fisted technique he could combine with Fish-Man Karate to create incredibly powerful punches.
And yes, Adam had chosen to officially say his style would only wield one blade. Currently, after reaching sufficient size, he had begun to use the Skillful grade Moonlit, passing Soaring Sun to Harribel.
It would take time to properly form his style, but he had many pieces in place, already being able to cut or not, and form soaring strikes.
On the side of his Haki, it couldn't be said that his progress was as grand, but it was still remarkably substantial.
Armament was still his top 'color', with him having developed massive amounts of it thanks to his titanic strength and will, granting incredible striking, cutting and defensive power.
Unfortunately, he hadn't been able to make any progress on allowing his Haki to 'Flow' yet, forcing him to look elsewhere to continue improving. As a result, Adam turned inward, deciding that 'Coating' his entire body wasn't enough for practice purposes and deciding to coat his insides as well.
This was a much harder challenge which excited him a lot. The only reason he even thought about doing something as crazy as this was because he could 'see' inside of himself to tell if he was succeeding properly and not causing any harm. What made him more interested was that he had only managed to do so on his bones so far as well, calling the process 'Forging' with his Armament Haki to temper his body.
Observation was kind of a mixed bag.
Adam had hit a sort of bottleneck in his development, not being able to reach any sort of 'Future Sight' due to lacking in high level battles to challenge him enough. His master and senpai weren't sufficient because they did not fight to the death or offer anything new to experience.
So once again, Adam had to get creative.
Already having developed significant range, being capable of covering almost 2/3 of Fish-Man Island, and having already formed a unique subtype of the Haki through his connection to and experience with 'water', Adam began to try and 'see' through greater amounts of people at once and run games to predict movements and possible movements depending of various actions. Playing an incredibly high-level 'game' of 'what if?' against any form of attack those around him could perform against him and how he could react.
Mostly mental training mixed with Observation, but it was much better than to stagnate fully.
Which really seemed to be the case with his Conquerors Haki.
It just would not grow without being challenged anymore. As simple as that.
Adam had a tremendous will to explore not matter the obstacle, but without being tested by the world, that will could not affect more of it.
He had managed to gain full control, being able to only affect those he singled out if he so wished, also being able to focus the entirety of his Conquerors Haki on a single person for greater effect. Adam had accidentally broken a few minds of pirate captains using that skill, but he wasn't in a rush to go beyond this level and focused on what he could instead.
Like many said, Adam was a monstrous child.
But it wasn't just because of how he was born.
People like Charlotte Linlin, Kaido and Oden were all born far beyond others in power, taking advantage of this power and growing through experience to reach where they stood, but Adam was different.
Instead of just fighting, acting rampantly or relying on just his natural abilities to carry him through, he trained relentlessly in every way he could under the guidance of experienced hands and great conditions to go further and at a much faster rate.
That was why, at the age of 9, he could be said to only possibly be surpassed by four known Fish-Men: King Neptune, Grandmaster Anguin, the Prodigious Jinbe, and the currently away Boss of the Fish-Man District, Fisher Tiger.
Even then, none had ever faced him with sword in hand either.
Beside himself, his two future crew members were also doing their best to grow in strength and skill.
Harribel obviously showed greater progress. Not only was she at least Half Fish-Woman, her aquatic side being of a Black Shark Fish, her single minded spirit for strength and similar interests in the blade allowed her to follow much of the path Adam had.
Although, she did focus fully on swordsmanship and water manipulation outside of physical training instead of going all the way like Adam. She knew full well she didn't have the talent necessary to split her focus, so she gave her all to the sword and water instead.
Having someone paving the path for her also contributed to her quicker uptake of combining Fish-Man abilities to the sword, and while she had been able to form soaring slashes, the concepts behind 'cut or no cut' were still difficult for her.
The hybrid Fish-Girl was making great progress though.
Morgiana was currently the weakest of the three, but that wasn't anything to be ashamed of because she also had the biggest gains in terms of technique.
With her specialization obviously being in leg-based skills, Adam had done his best to help that innate talent grow while also balancing her upper body abilities. As a result, she was taught a lot of Jujutsu and throwing techniques for her upper body, while quickly learning Fish-Man Karate's kicking arts for the lower.
Adam went a step further and taught her some of the different kicking and leg-based techniques of his past life she could adapt as she pleased. He also told her about how one could use friction caused by one's legs to form fiery attacks. Not wasting the opportunity, he taught her Rankyaku, Soru and Geppo to really give her a leg up in agility and versatility.
The girl hadn't managed to cause any sort of flames and obviously hadn't become any type of master in the Rokushiki techniques, but it gave her goals to and possibilities to develop on.
What was more surprising with the two was that they each unlocked a base forms of a Haki. Armament for Harribel and Observation for Morgiana.
The former was due to her Kuja heritage mixing well with her Fish-Woman half, quite similarly to Adam, and then having her training hellishly with someone who could and did use it. The latter gain hers because of her auditory abilities being far above the norm and Adam actually helping her develop her sensory and dodging capabilities intensely since she currently lacked durability compared to himself and Harribel.
Adam jokingly expected Harribel to develop Tekkai at one point and Morgiana to learn Kami-e with how differently they seem to approach combat.
The first preferred 'harder' styles while the second used 'softer' ones, not that Adam would tolerate them not having at least some of each in their approaches. In fact, Harribel naturally needed to be fluid in her sword strokes to combine water into it and Morgiana certainly wasn't afraid to hit hard, but currently they were less balanced than they could be.
Extremes were good, with most young people preferring 'Harder' styles thanks to their powerful and youthful bodies and spirits, while older individuals favored 'softer' practices as they placed less strain on their bodies, but the best always found a balance to achieve the greatest results. Take Mihawk for example, he was said to have the perfect blend of 'hard' and 'soft' in his bladework and while wielding one over 2m in length. One can't have a better example than a man who will be called the Strongest Swordsman and was said to match Shanks duels.
But again, there was no rush and Adam was happy to let them find their own paths in general.
For a ten and 8 year, the girls were plenty strong enough to be on the first half of the Grand Line. They certainly have beaten a fair number of pirates from with Adam and Jinbe's oversight to prove it.
And while the trio of monstrous children was growing far beneath the waves, away from the eyes of the world, the world abruptly came to them as the Whitebeard Pirates suddenly arrived one day, claiming the Island to be under their protection.
None of them had the chance to see Whitebeard due to him being invited up to the palace, but Adam knew that from now on very few pirates would be brave enough to try and raid the Ryugu Kingdom. He made a note to discuss that fact with the district later, letting them know that they might need to be a bit more proactive to maintain the current state of things over there
Overall, he thought it a welcome change and looked forward being able to take the next step necessary for his dream.
Author Notes:
Let's get this out of the way, Adam is basically the Fish-Man equivalent of what Oden could have been if he hadn't been fucking around his entire youth and trained till he almost dropped pretty much every day.
He is absolute peak Oden, with a brain and metaknowledge which allows him to widen his perspective and not limit himself to local abilities.
So obviously expect a bigger monster.
I'm still giving him limits to what he can achieve through Haki, but I'm also trying to have him be creative with what he has.
The idea of 'Black Bones' does appeal to me and the 'Transparent World' is basically from Demon Slayer while the mental training due to him being unable to unlock Future Sight is something I remembered from Baki as he trained to fight Miyamoto Musashi.
I think those are generally some good ideas when it comes to these arts.
His Conquerors being stuck as it is makes a lot of sense too, but is capable of what Shanks did to Admiral Ryokugyu on a much smaller scale. Control over power at the moment basically and he can't do infusion cause I think that's only when someone has powerful enough Conquerors Haki, which he doesn't have at the moment.
Now as for the girls, I would probably place them somewhere around Alabasta Arc levels, but very inexperienced.
Outside of them, I think Adam's actions gaining the eye of the Royal family is obvious and the ship thing was a bit spontaneous but it needs to come from somewhere.
The Marines taking notice of some of the changes down there also makes sense, especially with the claiming of bounties. I did also think adding subtly different reasons for Whitebeard claiming the Island as his was a nice little butterfly effect even if Fish-Man Island is probably one of the most difficult to reach Islands beside Wano.
Adding some of the effects of the changes in Fish-Man District were also fun little tidbits and I'm kind of looking forward to Fisher Tiger returning. I'm thinking that Jinbe would actually be stronger than him in this timeline since he's been more motivated and had a constantly improving sparing partner to fight with.
We never got to see much of Tiger, but he looked more like a brute brawler type than anything. Really tough and innately powerful, likely also having at least Armament, but I think this Jinbe could take him. The man would still be a leader because he would be more charismatic in general, but Jinbe should be stronger.
It's these little changes really.
So although more information focused, I do hope you still enjoyed.
We are currently 18 years before Luffy sets sail btw.