Luffy, Joy Boy and the Greatest War | One Piece Mega Theory

Greatest War

The greatest war has been mentioned several times by characters including Kaido, Oden, Doflamingo and Whitebeard. During Kaido’s introduction from the sky island, he asked Joker (Doflamingo) to hurry up so they can start the greatest war. However, Luffy defeated Doflamingo in Dressrosa and was taken to Impel Down. Oden also asked Toki to jump 20 years to the future so she can find what she was searching for. And before Whitebeard died, he told Sengoku that the day they are fearing is coming.

Don Quixote Doflamingo

In chapter 801, while Doflamingo was chained aboard a marine ship, he asked Tsuru who will be taking the empty throne that Roger left whether it will be the Celestial Dragon, The Navy / Marines, the Yonko, the Revolutionary Army, the Seven Warlords, the Worst Generation or the D clan.

The Empty Throne

During the Reverie in Marijois, King Stelly stood in front of The Empty Throne to take his oath. The Royal Guard explained that there is no one who sits in The Empty Throne and the 20 weapons were placed as an oath of allegiance when the world government was established 800 years ago. This however was a false notion as the great Imu or Im-sama is the one who sits in the throne and is served by the 5 great elders.

Royal Guard: No one is allowed to sit upon that throne. It is the Empty Throne. You see, the kings of the various nations are on equal standing and therefore they each make an oath not to seek control over the others.
Royal Guard: The 20 weapons that guard the throne were placed as an oath by the first 20 who created this world 800 years ago.
Royal Guard: While the greatest authority in the world is the five elders who are the most high ranking of Celestial Dragons there is no one king of the entire world.
Stely: If I sit up there I’ll be the king of the world!! (Chapter 907)

Imu Sama

Imu sama or the great Imu was asked by the five elders if he / she has decided upon another light to be erased from history. There are 4 posters with photos of Vivi Nefeltari, Shirahoshi, Luffy and Blackbeard. Who was the prior light that was erased from history? Could it be Rocks D Xebec?

In Chapter 908 Imu sits on the Empty throne holding a poster of Vivi Nefeltari.

Vivi Nefertari

Vivi Nefertari is the princess of Alabasta and daughter of King Cobra. She is an honorary member of the strawhats but chose not to join them after they defeated Crocodile. She met princess Shirahoshi of the Fishman Island and Rebecca of Dressrosa during the Reverie but was later on abducted or has gone missing as reported by Garp.

The Nefertari family belongs to the original 20 kingdoms who swore allegiance to the world government and the Gorosei calls them traitors for remaining in the lower realm.

Does the Gorosei know about the existence of the Ponegliff in Alabasta? King Cobra tells Robin that the duty of the Alabstan King is to protect the Ponegliff. How can the Kingdom of Alabasta who were part of the 20 kingdoms be the protector of the Poneglyphs?

Doflamingo: Over 800 years ago, When twenty kings from the twenty kingdoms came to the center of the world and established one massive power. That creation was today’s World Government and the creators, those kings brought their families with them to Marijoa, the holy land. Those nineteen families excepting only the Nefertari line of Alabasta who refused the honor have lived there ever since, ruling over the world. The descendants of the creators are known as the Celestial Dragons. (Chapter 722)

5 Great Elders: 800 Years ago, the Nefeltari dynasty was the sole bloodline of the first 20 to remain in the lower realm!!! In other words, they are traitors.

King Cobra: Generations of Alabastan Kings have been entrusted with protecting the Ponegliff. That is our only duty.
Robin: Protect it? Don’t make me laugh

Garp: Now this is a bit late in coming but there is one thing that happened that I haven’t told you about yet. Following the close of the reverie something happened just before we left.
Garp: The incident is regarding the Kingdom of Alabasta
Shirahoshi: Princess Vivi?

The Void Century

In chapter 395 / Episode 277, Professor Clover spoke with the Gorosei thru the denden mushi. He told them the reason why they were researching about the Ponegliffs is to uncover the true history of the 100 year void or the void century. He told them that they do not care about the ancient weapons, but more importantly, why the world government was established 800 years ago after the 100 year void and the extermination of the kingdom and its people. Before he was able to tell the name of the kingdom, he was shot and killed.

Professor Clover: The past belongs to all mankind. No one has the power to supress the desire to learn about a history that is not yet known.
5 Great Elders: Reading the Ponegliff makes possible the revival of Ancient weapons. It poses a danger to the world!! Even if you do not have evil intent, others may come along who intend to take advantage of what you’ve learned.
Professor Clover: Whatever lies in the past, if it is part of the history of humanity, then it should be accepted completely! If we confront everything that has happened without fear, we will be able to counter anything that will happen.
5 Great Elders: Such idealism
Professor Clover: I wonder about that. Isn’t it just convenient for you to disallow it? The greatest truth we seek in the world is not the Ponegliff but the reason for its existence. Why did the people of the past resort to writing on the stone. They dotted the world with these unbreakable tablets, onto which they carved their history. Isn’t this because they felt that their message would be eradicated if left only on paper and books?
Professor Clover: In other words, this is proof that the people who left the Ponegliff behind had an enemy!!
5 Great Elders: What is it you’re implying professor?
Professor Clover: If we assume these people were annihilated by their enemy then this enemy survived through the subsequent history and coincidentally, the 100 year void ended 800 years ago which marks the birth of the world government.
Professor Clover: If the government happened to be the enemy of the people who were annihilated, we can conclude that the 100 year void contains a history that was inconvenient to the world government and hence was erased!
Professor Clover: After reading ancient manuscripts and the few Ponegliffs that have been found, we’ve gradually discovered the existence of a nation which no trace now remains. What is clear from these manuscripts is the existence of an immense kingdom!!
Professor Clover: It appears that they once had enormous power but all information about this kingdom has been relentlessly erased. It is probably that these people understood they would be destroyed by this alliance of nations later called the world government and carved the truth of their existence onto pieces of stone which survive to this day known as the Ponegliffs!!
Professor Clover: Without a doubt, the so called ancient weapons could destroy the world. However, and more importantly, the history will reveal that the very existence and idea of this kingdom is in fact what the world government finds so threatening. Is that so?
Professor Clover: We still don’t know the nature of this threat but the key is this ancient kingdom that once thrived and its name was…

Lady Toki

Toki: My Age? I’m 26 years old. But I was born about 800 years ago. (Chapter 964)
Toki: I do not know. Only that Wano was my parents’ homeland. So there’s nowhere else for me to go except for Wano. (Chapter 965)

The Ancient Weapons

The ancient weapons were discussed in detail by King Neptune with Robin on Fishman Island. The Poneglyph in Skypeia pointed to the ancient weapon Poseidon which King Neptune described as the reincarnation of the mermaid princess. Meanwhile, Pluton was mentioned in the Poneglyph found in Alabasta guarded by King Cobra. The last ancient weapon Uranus has not yet been found but it could be possible that it is contained in Big Mom or Kaido’s Poneglyphs.

King Cobra: Why did you lie?
Robin: You knew? How disappointing.
King Cobra: The history of Alubarna wasn’t carved in that stone! It had all the information about the weapon you were after! Even its whereabouts. Even if you had told him what was written there, it would have been the end. The kingdom would have fallen into his hands
Robin: I don’t care about the kingdoms or people’s lives. None of that matters to me. But I had no intention of giving crocodile the weapon.
King Cobra: I don’t understand. Then why did you come here?
Robin: Events don’t always live up to one’s expectations. I was looking for the real ponegliff. Among the many Ponegliffs that exist in the world, it’s only the one that recounts the true history.
King Cobra: True history? What do you mean? Tell me something! Do you mean.. Can these scripts be spun together to tell of untold history? Is that what the ponegliffs are? (chapter 218)

King Neptune: For whatever reason, long in the past there existed powers deadly enough to destroy the world. Three ancient weapons bearing the names of gods. Pluton, Uranus and Poseidon.
Robin: And your daughter was one of them…
King Neptune: Indeed. If the rest of the world caught wind of this secret, everything would be thrown into chaos. Powerful forces would seek out the princess’s power. Both government and pirates alike.

Poneglyph

Nekomamushi: For generations, the Kozuki clan of Wano has been a line of Stone Masons cutting and carving stone. Even now, their skill with rock is unparalleled. Eight centuries in the past the Kozuki clan created indestructible stone documents. (Chapter 818)

Professor Clover: Reading the Ponegliff makes possible the revival of ancient weapons. It poses a danger to the world!! Even if you do not have evil intent, others may come along who intend to take advantage of what you have learned. Why did the people of the past resort to writing on the stone in order to convey a message to the future. They dotted the wold with these unbreakable stone tablets onto which they carved their history. Isn’t this because they felt that their message would be eradicated if left only on paper and books?(chapter 395)

Who is Joy Boy?

Joyboy was introduced in the Poneglyph Robin found in the forest of the sea. After Fishman Island was saved from Hody Jones and the threat of Noah crushing the kingdom, Nico Robin asked King Neptune who Joy Boy is. The King explained that Joy Boy was a person who lived in the surface more than 800 years ago and the poneglyph was his apology for not keeping his promise to the mermaid princess.

What was his promise to the mermaid princess? Is the rebirth of the two sovereigns connected to the fulfillment of this promise?

Gol D Roger and Oden also heard Neptunians or the Seakings talking about the birthing of their sovereign and another sovereign in a distant land.

Robin: Who is Joy Boy? I read the Ponegliff in the forest of the sea. Who was he apologizing to?
King Neptune: You can read that?
Robin: I am a survivor of Ohara. You don’t have to tell me, if you don’t want to stay.
King Neptune: No.. I will tell you everything I know. I trust you. Joy Boy is a person who lived in the surface 800 years ago. It was an apology for breaking a promise made with fishman island.
King Neptune: The contents of that promise are not clear but someone will come along to fulfill the promise in Joy Boy’s stead. At least according to the Royal Legend.
King Neptune: So we believe in that day and uphold our part of the promise by protecting Noah through the generations. For it is not until the day the promise comes about that Noah will fulfill its actual purpose.
Robin: After everything ended above the island I heard that Noah was taken to the forest of the sea by Neptunians. If Joyboy was meant to use Noah, could he have the power to control Neptunians?
King Neptune: No, the one who could use that power was the mermaid princess of the time.
Robin: As I thought. Meaning Princess Shirahoshi can do the same thing?
King Neptune: Yes, and I believe that latent ability came fully to the fore today.
Robin: Two years ago, I read a Ponegliff on an island in the sky that contained the location of an ancient weapon and that location was here. Could the mermaid princess who lived in the time of Joy Boy have another name?
King Neptune: A name that Princess Shirahoshi who has the same power will now inherit on her own. Her other name is in fact the Ancient Weapon Poseidon

Oden: If you steer into the wrong rapid currents, your ship will be smashed to pieces without getting any closer to Wano.
Oden: Until this point, there was a purpose to this country being closed. But now we must open its ports before the day that Joyboy appears (chapter 968)

Oden: It seemed like two stones would be quite the windfall but one of these two is not very important. It is an apology from someone named Joyboy.
Roger: What about the weapon that can control the Neptunians? Is it here? The stone on the island in the sky said this is where it would be. (chapter 967)

Oden: Wano.. No, the entire world awaits a figure and when that figure appears after an 800 year span this country must be prepared to welcome and work with them. I want you to open up Wano in my stead. (chapter 972)

Seakings

In chapter 968 / Episode 969, the seakings talked about their sovereign to be born in 10 years and will need 15 years to grow. They also talked about the other sovereign, most likely Joy Boy to be born in a distant sea. After reaching Laugh Tale, Roger remembered the voice and said that they came too early. Someone will find the One Piece and surpass them and jokingly said to Rayleigh that it will be his son.

Neptunians: The birthing is at hand! Our sovereign will soon be born and another in a distant sea the whales are delighted in anticipation of the day the two sovereigns shall meet again. We have been waiting for so long it is almost here and surely all will go well this time. Just 10 until birth and another 15 to grow.
Roger: I’m certain that voice was speaking the truth. Someone will be born and eventually surpass us!!! (Chapter 968)

Neptunians: Princess Shirahoshi, We have been waiting and waiting for you to be born. The ship was built for us to pull. It has been spoken off for years and years among us.
Shirahoshi: Is that why Noah is so large?
Neptunians: Every few hundred years, our soveriegn is born in the form of a mermaid for some reason. From the moment of your birth, you have been born our queen.

Fukaboshi: It’s as though the Neptunians protected the Noah so Luffy wouldn’t destroy it.
King Neptune: So the power great enough to destroy the world has finally awakened.

Princess Shirahoshi

After Luffy defeated Hody Jones, Princess Shirahoshi stopped him from further destroying Noah saying that the seakings are now pulling it. That was the first time Shirahoshi used her power to command the seakings. They were happy to finally meet their queen and told Shirahoshi that they have been waiting for a very long time for their sovereign to be born.

Then, as the strawhats leave fishman island, they were met by a pod of Whales. Remember the prophecy of the seakings that the “whales are delighted in anticipation of the day the two sovereigns shall meet again“

Oden: It seemed like two stones would be quite the windfall but one of these two are not very important.
King Neptune: It is an apology from someone named Joy Boy. Then you really can read this writing?
Gol D Roger: What about the weapon that can control the Neptunians? Is that here? The stone on the island in the sky said this is where it would be.
King Neptune: Well, there was a prophecy that little Sharley delivered not long ago that sent down a shiver in my spine. It is said that a mermaid who can talk to Neptunians will soon be born. They only come around every few centuries so perhaps…
Gol D Roger: You’re saying your daughter is going to be a weapon that will destroy the world one day?
King Neptune: It’s just a prophecy and every power depends on how you use it!!!
Oden: Who could have guessed that Poseidon would be a mermaid.
Gol D Roger: Hey Sharley, when is this mermaid princess going to be born?
Sharley: In 10! Ten years from now
King Neptune: Why would you take intereset in this Roger? I’m disappointed in you!!!
Rayleigh: It’s not the weapon that we’re after, Neptune. It’s the people who called it a weapon specifically the vast treasure those people left behind somewhere.

Noah, The Arc of Prophecy

The Noah that the seakings are bound to pull is also called the ark of prophecy and that it must never be moved until a certain day arrives. Then as the seakings pulled away the Noah towards the forest of the sea, they were asking how can Luffy hear them and remember about Gold Roger hearing them too. Also, They mentioned about the people who will fix the Noah.

King Neptune: The Noah!!! That’s the Ark of prophecy!!! It’s moving. No!!! We mustn’t allow any harm to come to the ark!! It must never be moved until a certain day has arrived!!(Chapter 636)

Neptunians: Was it my imagination? That human with the hat seemed to notice our voices. That can’t be! But it did happen once before. The ship is falling to pieces. can it be fixed? Can it be used? I cannot say… We will need their help to fix it but it is a different age now. Can It be fixed? I hope so. Before the promised time arrives (Chapter 648)

Tom is a Fishman who built Roger’s Ship

Gold Roger’s ship Oro Jackson was built by Tom who is also a fishman. Apparently he was in possession of the blueprints of Pluton. Upon seeing the blueprints, Franky asked if any HUMAN can make such a thing. In Water 7, Franky built the strawhat pirate’s ship “Sunny Go” from the tree of Adam which was also the same wood used in Oro Jackson. It’s counterpart, Eve, has its root connected to fishman island.

Why does Fishman Island possess TWO of the THREE ancient weapons? Is Franky pertaining to the Noah when he asked how can a human make such a thing?

Sharley’s Prediction

There are two prominent figures in One Piece who seems to have an ability to foresee the future. The first is Madam Sharley and the second is Higurashi Kurozumi

At an early age, Sharley was able to predict the marriage of King Neptune and Otohime and the birth of the Mermaid Princess Poseidon. When Luffy arrived in Fishman island, she saw a devastating future that the fishman island will be destroyed by Luffy. However, Luffy saved fishman island from Hody Jones and the threat of Noah. Because of this, Sharley destroyed her crystal ball saying she doesn’t wish to see a terrifying future but the premonition she saw may happen anytime in the future.

Higurashi Kurozumi

The second person who has the ability to foresee the future is Higurashi Kurozumi. Oddly enough, Higurashi was seen to be imitating a young Shiki which could possibly point out that she may have traveled with Kaido as part of the Rocks crew. At that time, Kaido was an apprentice of Rocks. Kaido’s back story has not been revealed yet but this could be the reason why he and Higurashi are in Wano at the same time.

Kurozumi Higurashi: I can see it! A vision of the future! You will be the Shogun. It was Kozuki Sukiyaki’s fault for being born. That’s right! If it weren’t for him, you would have been a Shogun that day! Who I am does not matter! I have been out of the country! Its been a terrible ordeal. (Chapter 965)

D Clan

In chapter 764 / Episode 703, Rosinante Donquixote learned that Law was a D and revealed that the D clan are the natural enemies of the GODS or the Celestial Dragons. Corazon chose to tell this secret despite being a previous celestial dragon himself.

However, Corazon did not tell Law that he and Doflamingo were Celestial Dragons. Only during their fight between Doffy that Law learned about them being a celestial dragon. How can a celestial dragon help a member of the D clan and how can members of the D clan serve under the world government and the marines?

Up to this date, Law is still trying to search for the history of the D Clan

Rosinante: You have the secret name of D!! That means you’re one of the fateful few, the people of the D. Back in my hometown, children were scolded into behaving by this threat..
Rosinante: “If you don’t behave, you’ll be gobbled up by a D”
Rosinante: Every once in a while, when another person of D becomes known, the elderly raise an eyebrow and murmur.
Rosinante: “The D will always cause another storm!!
Law: What’s that supposed to mean? Am I supposed to be a monster or something?
Rosinante: Perhaps. No One knows the truth. But the name lives on in the dark shadows of history around the world!!
Rosinante: In one area, the people of the D are known as “The enemies of the GODS”
Rosinante: And if you view the Celestial Dragons as the GODS in this case, then perhaps your people’s goal is the very destruction of this world.
Rosinante: But with an entirely different meaning than the way Dofy intends it
The people of D no doubt have a philosophy that pits them against the GODS

There are six known members of the D Clans who are pirates including Luffy, Blackbeard, Law, Ace, Rocks and Roger. Garp and Saul are marines, while Dragon is a revolutionary. Ace’s mother Portgas D Rouge was not a pirate but is affiliated with both Roger and Garp.

Whitebeard

Before Whitebeard died in the Battle of Marineford, he recalled Roger’s words about the D clan, the One Piece and the great war. He also told Blackbeard that he was not the man that Roger was waiting for.

Gol D. Roger: Do you know what the government is calling me nowadays? “Gold Roger.” They’re wrong. My name is Gol D Roger!
Whitebeard: I see people with that D from time to time. There’s one called Teech in my crew. What is that D Thing anyway? You wanna know? Then I’ll tell you. A long time ago…

Whitebeard: You’re not him. The man Roger is waiting for is definitely not you Teech. Just as some who inherited Roger’s will. Someone will eventually do the same for Ace. You can sever bloodlines but their flames will never be extinguished. (Chapter 576)
Whitebeard: It has been passed down like that since the ancient times! Someday, someone will arise who will challenge the world and shoulder centuries of history. (Chapter 576)
Whitebeard: Sengoku, you and the world government fear the great war that will come to this world one day! I’m not interested in the treasure, but when it is found the whole world will be turned upside down. Someone will find it. That day will come. The One Piece Does exist. (Chapter 576)

Will of D

According to Whitebeard, the “Will of D” is passed on by members of the D clan to arise and challenge the world. Here are the members of the D clan that are now dead.

Is Nico Robin Gol D Roger’s Daughter?

Whether Nico Robin is part of D Clan is still questionable but there are hints that she might be part of the D clan as her father is still a mystery. One possibility is that Nico Robin is Gol D Roger’s daughter. Her mother Olvia left Robin when she was 2 years old in Ohara and Jaguar D Saul and Olvia were seen smiling during their death as they tell Robin to escape.

Robin is currently 30 years old. Oden and Roger met 26 years from the current timeline and in chapter 968 Roger tells Rayleigh that his son will surpass him and the latter replied you don’t have one. And in chapter 966 Roger carries young Hiyori Kozuki telling Rayleigh that he hasn’t spent time with a baby in ages with Rayleigh replying that it reminds him of the old ages.

Here are some facts about Nico Robin:

1. Olvia left Robin in Ohara when she was 2 years old (pre timeskip) (Chapter 393)
2. Oden and Roger met 26 years ago (post timeskip)
3. Gol D Roger was executed 24 years ago (post timeskip)
4. Robin was 8 years old when Ohara was destroyed (pre timeskip)
5. Robin is currently 30 years old.
6. If you can’t leave your child, then don’t come. We’ll fulfill your husband’s wishes

Nico Robin’s age based on the One Piece timeline

• 30 years old (current age of Nico Robin)
• minus 22 years – Ohara was destroyed (Nico Robin @ 8 years old)
• minus 2 years – Gold Roger was executed (Nico Robin @ 6 years old)
• minus 1 year – Oden returned to Wano (Nico Robin @ 5 year old)
• minus 1 year – Roger and Oden meet, Roger carries Hiyori (Nico Robin @ 4 years old)
• minus 2 years – Olvia left Robin in Ohara (Nico Robin @ 2 years old)
• minus 2 years – Nico Robin was born

Blackbeard

Blackbeard: Pack your bags!! Onto the ship, If the navy’s going to take it, we might as well claim the prize!!! (chapter 956)

Rocks D Xebec

In chapter 907 / episode 958, Sengoku tells the marines Big Mom and Kaido belong to the Rocks crew headed by Rocks D Xebec. During the God Valley incident, a pirate alliance between Gol D Roger and Monkey D Garp fought against the crew.

Who inherited the Will of Rocks D Xebec?

In the battle of God Valley, three D clan members fought including Monkey D Garp, Gol D Roger versus Rocks D Xebec. Members of Rocks crew were Whitebeard, Big Mom and Kaido. There were no evidence that Rocks died as Sengoku explained that the island disappeared but if he really did die, then his WILL OF D should have been passed on and to whom?

There could be a possibility that Im or the Great Imu could have chosen to erase Rocks D Xebec from history as the proof of his existence were eradicated but it could also be that he is locked up alive somewhere either by Kaido or the world government.

One other instance of two D clan members fighting is Portgas D Ace and Marshall D Teech in Mocktown. To protect his brother Luffy, Ace fought with Blackbeard but got defeated due to the powers of the Yami Yami no Mi.

After Blackbeard defeated Whitebeard in the Battle of Marineford, Whitebeard told him that someone will inherit the Will which is known as the “Will of D“

Luffy’s Promise to Princess Shirahoshi

In Chapter 653 before the strawhats left Fish Man Island, Princess Shirahoshi asked Luffy if he can take her to a stroll in a real forest. Luffy promised to Princess Shirahoshi that he will take her to a trip with Brook subtly emphasizing that promises are meant to be kept until DEATH. This also signifies why the promise of Joy Boy has lived through out ages for 800 years and why the Mermaid Princess Poseidon is reincarnated every few hundred years hoping that the promise will someday be fulfilled.

Joyboy and Wano

When Roger and Oden reached Laugh Tale, they found out about the trues history of the world. Roger wished that he had also lived at the same era as Joy Boy. More than 800 years ago, the Kozuki were stone masons who carved out the history to the Poneglyphs to protect the history of the world.

As Oden returns to Wano, he comments that the reason why the Kozuki clan closed off its borders was to protect itself from external forces and Wano must open its borders before Joy Boy returns. Before he died, he ordered his retainers to open Wano’s borders before the arrival of the figure.

Momonosuke is not Joy Boy

Momonosuke could not be Joy Boy for 3 reasons. First is that he is already alive when Oden traveled with Roger and the seakings talked about the other sovereign to be born in a distant land. Second, Oden asked Toki to jump 20 years into the future so that she can find what she is looking for. Third, King Neptune told Robin that Joy Boy cannot control the seakings and only Poseidon can do that. Meanwhile, Momonosuke is able to control Zunisha just like how Poseidon can control the seakings.

Momonosuke may be related to the person who punished Zunisha and ordered to roam the seas and never to stop.

Momonosuke may not be Joy Boy but what could be his role in Joyboy’s story? I can only assume from here but Momonosuke may be the key to unlocking Joy Boy. Just like Shirahoshi did not know that she is Poseidon, someone must be able to guide Joy Boy.

Yamato and Oden’s Journal

The D clan were unknown to Oden until the time they reached Laugh Laugh tale where Oden wrote on his journal that they finally found the answers to the D clans and the ancient weapons. According to Yamato, it is fate that allowed Momonosuke to meet Luffy and bring to Wano

Luffy is Joy Boy

Based on all the clues we have gathered, Luffy appears to be Joy Boy and he is now in Wano with Momonosuke. Wano’s borders are still closed but it may be opened very soon as the dawn arrives in Wano.

1. Toki mentioned to Oden that she has been jumping several times from 800 years ago.
2. As Oden Returns to Wano, he tells the Roger Pirates that Wano must open its ports before the day that Joyboy appears.
3. Oden mentions that Wano or the entire world is waiting for the return of a certain figure.
4. During Oden’s execution, He orders his retainers to open Wano before the figure returns.
5. Luffy fell on the sea in chapter 1014. He needs to return to the battle and before that time happens, Wano must be prepared to welcome and work with THEM.
6. The Poneglyph in the forest sea floor contained the apology of Joy Boy to the mermaid princess.
7. King Neptune told Robin that Joy Boy was a figure from 800 years in the past and someone will come along to fulfill the promise.
8. The seakings mentioned that their queen will be born in 10 years and the other supreme will be born on a distant land.
9. Oden, Gol D Roger and Luffy can hear the seakings.
10. Momonosuke was already alive when Roger and Oden heard the seakings talking about the other sovereign.
11. Princess Shirahoshi is Poseidon and can control the seakings or Neptunians while Momonosuke can control Zunisha
12. Neptunians told Shirahoshi that every few hundred years, a mermaid princess is born to become their sovereign.
13. The seakings mentioned that they will have to bring Noah to them to repair it but it’s already a different time. They left Noah in the forest sea floor.
14. Tom the shipwright was a fishman who built Gol D Roger’s ship.
15. Tom’s apprentice Franky has the blue print to the ancient weapon Pluton. It is possible that the Noah is Pluton and that Franky will be the one to repair Noah.
16. Whitebeard told Blackbeard that the person Roger was waiting for is not him and he did not inherit Roger’s will.

Who are the other possible Joy Boy?

1. Sabo – Luffy, Ace and Sabo were brothers although Sabo is not a D. He serves under Monkey D Dragon as a revolutionary

Is Joy Boy a title or a person?

1. According to the seakings, The mermaid princess Poseidon is born every few hundred centuries and that the other sovereign to be born on a distant land and the two sovereigns will finally meet again.
2. Joy boy was not sent from the past just like Toki jumped to the future. He will be reborn.
3. Joy Boy is not a title but a personification of the sovereign.
4. The other sovereign (Joyboy) must realize that he is Joy Boy just like Shirahoshi was not told she was Poseidon until she was able to command the seakings.
5. Joy Boy was allied with Fishman Island, Wano Kuni and Zou.
6. The alliance with Alabasta is somehow questionable as they were part of the first 20 kingdoms but were left in possession of a poneglyph and the directions to Pluton.

Here are my thoughts

1. Rocks D Xebec could possibly be the other Joy Boy, Kaido was referring to. If Rocks D Xebec is dead, Gol D Roger may have inherited Rocks Will of D which is why he ventured on the grand line to find the One Piece. Another possibility is that Kaido may also have been sent from the past to prepare the great war
2. Meanwhile, Garp did not pursue the One Piece simply because that will be against the celestial dragons.
3. It is also possible that Joy Boy’s promise to the mermaid princess is to destroy the barriers and the walls that divide the seas so they can all live freely and fishman island stands below the red line.