Ace had already lived in this world for several years.
Or rather, he should have been called Gabriel.
The real Portgas D. Ace had died long ago. The Ace who now walked the seas was a soul from another world, a man who had unknowingly taken over this body after crossing the boundary between lives. Gabriel had once been an ordinary young man from the modern world, never expecting that fate would pull him into the world of One Piece, let alone place him inside the body of one of its most important characters.
Ironically, Gabriel had been a devoted fan of the series.
Yet the world he found himself in was not exactly the same as the story he remembered.
When he first awakened in this body, the people standing before him were none other than Marine Hero Garp and the leader of the Revolutionary Army, Monkey D. Dragon. The disbelief in their eyes had been unmistakable. What unsettled Gabriel the most was the truth he slowly came to understand. The original Ace had died, and that death had been the reason Gabriel had taken his place.
This alone was already far removed from the story he knew.
He had crossed over when Ace was only ten years old, still living under Dadan's roof in Windmill Village. Not only had Ace died prematurely, but Luffy, the child of destiny, had also been stabbed and nearly lost his life. On top of that, the Marines had gained an absurdly powerful Vice Admiral, Enel himself.
Enel, the former ruler of Skypiea and the man who wielded the power of the Rumble Rumble Fruit, had somehow become a Marine.
Even more outrageous, he was now counted among the Marines' so called Four Great Monsters, standing alongside Sakazuki, Borsalino, and Kuzan.
Despite all these shocking deviations, Gabriel could not suppress his excitement. He had not only entered the world of One Piece, but had become Ace, Luffy's older brother. From the very beginning, he held a role worthy of a protagonist.
So he embraced Ace's identity completely.
Luffy, the character he once admired from afar, was now his little brother. Shirahoshi, Robin, Nami, Hancock, all of them existed as real people in this world. But Gabriel understood something very clearly. This world was cruel. Strength alone dictated truth, and only those with power could protect what mattered to them.
If he wanted a future worth living, he had to grow stronger.
He sought out Garp and asked to be trained, dragging Luffy and Sabo along with him. From that day on, Garp returned to Windmill Village every month, enduring endless scoldings from Sengoku because of it. Yet Ace's brush with death had shaken him deeply. When Ace stopped calling him "old man" and instead called him "Grandpa," Garp agreed without hesitation.
He trained them brutally and without restraint.
Perhaps it was the effect of crossing worlds, but Ace's talent was terrifying. Within a single year, he fully awakened and mastered all three forms of Haki: Conqueror's Haki, Armament Haki, and Observation Haki. Garp was not particularly surprised by the awakening of Conqueror's Haki. After all, Ace's bloodline spoke for itself.
What truly unsettled him was Ace's ability to hear the Voice of All Things.
On top of that, Ace rapidly learned the Six Powers and even mastered Life Return. Luffy's later control over Haki and the development of his Devil Fruit were also heavily influenced by Ace's guidance. Sabo progressed just as quickly, eventually choosing to follow Dragon, but this time, he never lost his memories.
Because of Ace, the paths of all three brothers changed completely.
At seventeen, Ace set sail in accordance with the original timeline. As expected, he obtained the Mera Mera no Mi and carved a blazing path from the East Blue through the Grand Line and into the New World. He challenged Whitebeard head on.
Unlike the original outcome, he was not crushed immediately. The two exchanged dozens of blows before the older pirate finally prevailed. Experience still mattered, and Whitebeard's strength was unquestionable.
Afterward, Whitebeard extended his hand and spoke the words that echoed across the seas, asking Ace to become his son.
Ace had initially refused, but genuine respect for the old man and the need for a powerful backer ultimately led him to accept. Gradually, he became part of the Whitebeard Pirates. With the world's strongest man behind him, his confidence grew without limit.
From there, he rampaged across the New World, the Grand Line, and even the Four Seas before returning once more to the New World. He challenged Emperors, elite commanders, and Marines alike, reveling in battle.
By now, Fire Fist Ace had become a name feared across the seas, a pirate capable of contending with Admirals themselves. On several occasions, his actions nearly ignited open conflict between the Marines and the Four Emperors. Each time, Whitebeard stood firmly behind him.
In one incident, Whitebeard personally intervened.
Kaido had ambushed a heavily injured Ace, and the old man responded by storming Onigashima alone. With overwhelming power, he crushed Kaido's forces and forced even the Three Calamities' subordinates into submission. His message to the world was clear. If Ace died in a fair fight, he would accept it. But if underhanded methods were used, Whitebeard would answer with force.
Even in old age, he was still a monster.
Another name could not be ignored: Blackbeard.
Originally destined to be a terrifying villain, Blackbeard's path diverged early. He sensed Ace's hostility the moment Ace joined the ship, yet fate played its own games. Blackbeard obtained the Dark Dark Fruit during a mission and left the Whitebeard Pirates without killing Thatch or betraying the crew. He departed peacefully, avoiding the bloodshed that once defined him.
As for Ace's so called advantage, it was not a system or divine intervention. His soul had been refined through the crossing of worlds, enhancing his natural talent. Training yielded twice the results with half the effort, allowing him to master Haki, the Six Powers, Life Return, and the Voice of All Things far earlier than anyone else.
Ace simply called it Talent Enhancement.
"Ace, stop stuffing your face already."
On the deck of the Moby Dick, Marco and the others watched as Ace ate and drank without restraint. Someone shoved a barrel of sake toward him.
"You want a drinking contest?" Ace grinned. "I'm in."
Jozu's eyes gleamed with enthusiasm.
Laughter echoed across the deck as Whitebeard sat at the head of the table, drinking deeply while watching Ace with clear satisfaction. This was everything he had ever wanted. Not power, not treasure, but family.
Just as the celebration peaked, a News Coo landed on the railing. A nearby pirate paid in Berries and grabbed the latest paper.
"The Worst Generation has been wiped out on Sabaody Archipelago. Only the Straw Hat Pirates haven't landed yet."
"Straw Hat Pirates?" someone muttered. "That sounds familiar."
"Isn't their captain Monkey D. Luffy, Ace's little brother?"
Ace froze. He walked over, took the newspaper, and frowned as he read. Supernovas were being hunted, and Luffy might be in danger.
He had not seen his brother in years.
Suddenly, Whitebeard began coughing violently.
"Pops!"
Ace rushed to his side, worry clear on his face. Whitebeard had truly grown old.
"You shouldn't drink anymore," Ace said firmly.
Whitebeard laughed it off, but Ace's expression remained serious.
"I need to leave for a while," Ace said. "Luffy may be in danger, and I'm going to find someone who can treat or ease your condition."
Whitebeard dismissed it, but Ace was already set on his decision. He leapt into the air, flames igniting beneath his feet as he soared into the sky, disappearing toward the horizon in a blazing streak.