It had already been three years since Arthur obtained his sword, and during those years, his training had grown more intense than ever before.
Rayleigh had increased the difficulty of their sessions to match Arthur's rate of progress, especially after learning that his son had awakened his Conqueror's Haki earlier than he expected.
When Rayleigh first discovered it, he immediately released his own Haki to test Arthur's reaction, only to see Arthur unconsciously defend himself with his own Conqueror's aura, as if by instinct.
It was then that Rayleigh realized that Arthur's potential might be far beyond his imagination.
After that day, Rayleigh spent an entire year teaching Arthur the concepts of Haki in a structured manner.
He guided him on how to sense it, how to control it, and how to blend it with his own fighting style.
In that same period, they sparred almost daily, sometimes until the sun went down, sometimes until their bodies could barely move.
Arthur, in return, taught Rayleigh something he had kept to himself for years — the Total Concentration Breathing technique.
When Rayleigh began practicing it, he immediately noticed the changes in his own body.
His breathing became sharper, his movements lighter, and his strength, which had slightly dulled with age, began to return to its peak.
It amazed Rayleigh that something so simple could refine his already formidable power.
"So this is the secret behind your strength despite being so young?" Rayleigh asked one evening as they rested by the shore, both of them breathing heavily after another exhausting session.
"Not exactly," Arthur answered. "It helps me grow faster, but I still have to put in the work. I train every single day.
But now that you've learned it, Father, things will become more interesting. I'll have to push even harder."
When the two of them sparred after that, the islands they trained on often ended up in ruins. Trees were split, craters formed, and the very ground bore the marks of their battles.
From afar, it looked like an army had fought there, when in truth, it was only the two of them.
As the years continued, Arthur's control over his Conqueror's Haki became sharper and more refined.
His Armament Haki also improved to the point where Rayleigh had nothing more to teach him.
Rayleigh had once said that Haki truly develops only through experience and battle, not through theory.
So from then on, Arthur trained by fighting opponents outside their home, testing his limits against real threats.
This led Arthur to take up the habit of hunting pirates who docked at Sabaody. Many of them were from the New World and came to sell slaves or trade in illegal goods.
Arthur would wait for these kinds of pirates and eliminate them, one by one.
The Marines turned a blind eye, partly out of fear, and partly because many of them were secretly connected to those same pirates.
The only difference now was that Arthur's interference was cutting into their profits, which made them resent him but left them powerless to act. Everyone knew that Rayleigh's son was far too strong to be handled easily.
Arthur became known as a bounty hunter, though he never saw himself as one. He only did it to train and to test his swordsmanship.
The more he fought, the more precise his movements became, and the more he understood the flow of battle.
He eventually reached a level of awareness so refined that his strikes flowed naturally, as if guided by instinct — something close to the Breath of All Things.
Each pirate he killed added experience to his craft. Over the span of three years, the total bounties from the crews he defeated had reached nearly five billion berries, though Arthur never cared much for the money.
Seeing his son's growth, Rayleigh eventually stopped sparring with him. There was nothing more he could teach through direct combat.
Instead, he began waiting, silently, for the day Arthur would decide it was time to leave and see the world for himself. That day seemed close. But before it came, something unexpected happened.
-------------------
One afternoon, while Arthur was out on his usual hunt, a familiar presence entered Shakky's bar.
When Rayleigh looked up, he saw a man stepping through the doorway with a calm smile, his red hair unmistakable even from afar.
"Shankkun," Shakky greeted warmly as she guided the visitors inside.
Rayleigh, who was sitting at his usual spot with a bottle beside him, turned toward the voice and saw his former disciple — Shanks, the captain of the Red Hair Pirates.
The moment he looked closer, however, he noticed something different. Shanks was missing an arm, and the old straw hat that once rested on his head was nowhere to be seen.
"Ray-san," Shanks greeted with a smile, lifting the large bottle of alcohol he carried in his remaining hand. "I brought you a gift. Thought it was about time we shared a drink again."
Rayleigh's eyes narrowed slightly. "What happened to you, Shanks?" he asked, though his tone was calm, almost curious.
Around them, the Red Hair crew began unloading crates and offering bottles and gifts to Shakky, who directed them with her usual composed smile.
"It's a small price to pay for the next era," Shanks said as he looked down at where his arm used to be. There was no regret in his voice, only quiet certainty.
When Rayleigh saw that expression, he understood immediately and didn't press further. He knew there were things better left unspoken.
"The hat," Rayleigh said after a pause. "It's with that person now, isn't it?"
Shanks nodded with a faint smile. "Yes. And I have no doubts he will bring the new era."
Satisfied with that answer, Rayleigh smiled as well. "Then I suppose that's good enough for me."
They both began drinking, laughing quietly as the Red Hair crew joined in. The bar quickly turned lively, filled with laughter, music, and the smell of alcohol in the middle of the day.
Some time later, Arthur returned home. As he approached the bar, he noticed the sound of loud conversation and laughter coming from inside, something that rarely happened.
When he entered, his eyes immediately went to the group gathered around the counter.
At the center of it all was a man with bright red hair and a missing arm, laughing with his father as if they were old friends. Arthur stopped for a moment, recognizing him immediately.
The Red Hair crew noticed him as well. Benn Beckman turned first, followed by Yasopp, Lucky Roux, and then Shanks himself.
All of them looked at Arthur in silence for a brief moment. There was something about him — the calm confidence, the controlled strength that seemed to radiate from his very presence.
Then, one by one, the four of them smiled.