At that moment, on an island somewhere in the Calm Belt…
Rayleigh happened to be away for the day, while Hancock had returned to Amazon Lily.
Which meant—
"Gum-Gum—Jet Fire Fist Gun!"
"Fire Fist!"
Two blazing attacks collided head-on.
BOOM!!!
When it came to controlling flames, however, Ace was ultimately still the superior one as the user of the Flame-Flame Fruit.
He absorbed every bit of fire wrapped around Luffy's attack, then continued charging straight toward him.
The flames around Luffy's fist vanished, but the Armament Haki coating it remained. His punch lost none of its momentum and slammed directly into Ace's face.
Ace's features warped from the impact, his entire face twisting violently to one side.
At almost the exact same moment, Ace's own attack connected.
Luffy had no time to dodge. Flames struck him in the waist, and he gritted his teeth as the impact sent him flying backward.
Both brothers dropped from the air.
One had taken a hit to the waist.
The other had been punched in the face.
Looking at them now, the scene was almost identical to the battles between Garp and Roger decades ago.
…
"I'M ON FIRE! I'M ON FIRE!!!"
Luffy hurriedly tore off his burning shirt and threw it aside before putting out the remaining flames.
The skin around his waist had turned bright red, but he was still grinning.
"Hahaha! I hit Ace too! That means I've caught up to you this time, right?"
Ace got back to his feet and stared at him.
"What are you talking about? You've still got a long way to go."
"If my attack can hit you that cleanly, your Observation Haki obviously still isn't good enough!"
"But I hit you too."
Luffy pointed at Ace's face as he pulled his clothes back on.
"And your face still hasn't gone back to normal. You look hilarious right now! Hahahaha!"
Aside from having his face knocked sideways, Ace had also grown a rough layer of stubble along his jaw. He had been so busy training lately that he had completely forgotten to shave, giving him a noticeably more rugged appearance.
His beard was not the only thing either.
Ace had recently noticed that his nose kept itching.
Apparently, his nose hair had started growing longer too.
The moment Luffy laughed at him, Ace hurriedly rubbed his face back into place, then punched Luffy on top of the head.
"That still doesn't mean you've caught up to me."
"You only just learned how to consciously release Conqueror's Haki. How could you possibly understand this already?"
Ace clenched his fist.
Conqueror's Haki began gathering around it, only to disperse again a moment later.
"I can only draw out a tiny amount right now, but it definitely strengthens my attacks."
"Still, if we were seriously fighting to decide a winner…"
Ace's eyes shifted toward Murakumogiri standing upright in the distance.
"I could try using Pops's weapon."
The Whitebeard Pirates had delivered Murakumogiri to him some time ago.
Recently, Ace had been considering how to combine the Conqueror's Haki he was beginning to understand with his flames and channel both through Murakumogiri.
It would not merely increase his combat strength.
The weapon itself carried enormous symbolic meaning for the Whitebeard Pirates.
Ace was no longer fighting only for himself.
There were countless people standing behind him now.
Luffy had no problem with Ace using a weapon during a fight.
Among the people he knew, plenty carried weapons of their own. Aside from Garp, Sanji, and a few others, most strong fighters had something they were comfortable using.
Complaining that weapons made a fight unfair would be ridiculous.
What kind of pirate would say something like that?
If weapons were unfair, then Mihawk and Zoro might as well retire immediately.
Rayleigh had even asked Luffy before whether he wanted some kind of weapon to support his fighting style.
Luffy had refused without hesitation.
Compared to carrying a weapon, he had always preferred his fists.
But the moment the subject shifted back to Haki, Luffy immediately shook his head and started complaining about Rayleigh playing favorites.
Rayleigh kept talking about "building a proper foundation" and refused to begin teaching him the next stage of Conqueror's Haki.
Ace understood why.
Luffy had figured out many things on his own.
Even though Garp had subjected him to brutal training since childhood, and even though Cain had provided plenty of theory along with some practical demonstrations in the past, Luffy's actual foundation in Haki was still surprisingly weak.
Even now, he had not fully mastered incorporating both Armament and Observation Haki into combat.
Otherwise, he could have easily used the flexibility of his rubber body to evade Ace's previous attack.
Rayleigh's approach naturally had a reason behind it.
Ace had once asked him about it, and Rayleigh had explained his assessment of all three brothers.
Luffy was the type who improved in the middle of battle.
More specifically, he tended to make his greatest breakthroughs only when fighting desperately with his life on the line.
That was why his current priority was strengthening his fundamentals and becoming completely comfortable using Haki.
Ace, on the other hand, was naturally gifted.
His ability to understand and learn Haki was extremely high. As long as he trained seriously and put in the effort, advancing to the next stage came relatively easily.
Unfortunately, Whitebeard's protection had caused him to neglect certain aspects of his growth in the past.
His Conqueror's Haki, for example, had actually been weaker than Kid's.
Then came the pressure of eventually inheriting responsibility for the Whitebeard Pirates.
With so much weighing on him, his progress had become even slower.
Otherwise, with Ace's talent, he might already have mastered Conqueror's Coating instead of barely being able to summon a trace of it.
What Ace needed now was to readjust both his condition and his mentality.
As for Cain…
According to Rayleigh, back when Cain had been desperate to master Conqueror's Coating so he could save Ace, he had practically forced Rayleigh to train him nonstop.
Cain was the worst possible combination—
Talented and completely reckless with his own life.
Worse, his fundamentals were absurdly solid.
Give him a small hint, enough time to understand it, and an opportunity to practice, and he might make a breakthrough while sitting around doing nothing.
Thinking about Cain, Ace naturally shifted the conversation toward him.
"Quit complaining. Your fundamentals really do need work."
"Just look at Cain. That bastard is way ahead of both of us now."
"Though I guess it makes sense. Anyone who survived the old man's training would naturally have a stronger foundation than us."
"Yeah. Cain's gotten really strong."
Luffy dropped onto his back and stared up at the sky.
"That's exactly why I have to surpass him and steal him back."
Ace sat down beside him before lying back as well.
"So you really mean it?"
"Two years from now, you're actually planning to pick a fight with every Emperor?"
"Of course!"
Luffy clenched his fist.
"Cain is our brother."
"And he's my crewmate."
"I'm not just going to leave him there while he joins somebody else's pirate crew."
"Even if it's Shanks."
"Even if it's Big Mom, who calls Cain family."
"Or that horned gorilla who's Yamato's dad—Kaido of the Beasts!"
"I'm taking Cain back from all of them!"
Ace looked at him, then shook his head with a laugh.
"I'm impressed."
"You actually got all their names right in one go."
As the two continued talking, their Observation Haki suddenly warned them at almost exactly the same moment.
A powerful presence was approaching.
Both brothers immediately reacted.
BOOM!!!
Something crashed down from the sky, blasting an enormous cloud of dust into the air.
Luffy frowned.
The presence felt strangely familiar.
Ace, however, instantly remembered Mock Town.
The same cloud of dust.
The same arrival from the sky.
The exact same entrance.
There was no need to guess who had come.
"Luffy, run! It's the old ma—"
Ace never finished.
Two enormous hands shot out from the dust.
One clamped down on Ace's head.
The other grabbed Luffy by the collar and lifted him off the ground.
From within the smoke, a pair of beast-like crimson eyes filled with terrifying "love" pierced straight through the haze.
Then a familiar voice slowly followed.
"It's been a while, Luffy! Ace!"
"Your grandpa came to see you!!!"