One Piece: I Turned the Four Emperors into Ninjas

Youya gained a golden finger.

As long as he trains a ninja, he receives a reward.

From then on, monsters said to be Four Emperors who could use powerful ninjutsu suddenly appeared across the seas.

Kaido learned ninjutsu such as Lightning Release: Kirin.

Big Mom learned ninjutsu such as Lava Release.

Whitebeard learned ninjutsu such as Earth Release and Water Release.

Roger learned Flying Thunder God and Fire Release. They called him Fire Release Roger, the Flash of the Sea.

Garp learned the Eight Gates. Just how strong would he be?

What kind of excitement would come to this world when the pirate world merged with chakra ninjutsu?

Even Imu and the Five Elders said it was great and wanted to learn.

Many years later.

Before his execution, Roger revealed the secret behind his abilities.

He said that he had learned all his ninjutsu on the ninja island called Laugh Tale.

So everyone set sail and headed out to sea.

The world entered the Age of Ninjas, with everyone eager to learn ninjutsu!

This novel and its characters are entirely fictional. Any resemblance is purely coincidental. Do not imitate.