One Piece: I Can Upgrade My Haki

Rain is a seventeen-year-old boy from the East Blue, born into a martial arts family in the South Blue. He has studied Haki under his grandfather since childhood, but his average talent has kept him at the novice level. When he was ten, his pirate father was executed by the Marines, and his mother died of grief. Left all alone, Rain vowed to become a great pirate and change this unjust world.

During a near-fatal battle with East Blue pirates, Rain awakens the Haki Upgrade System! The System lets him gain Haki experience through battle, absorbing other people's Haki, and completing special missions, allowing him to keep leveling up his Haki. Every upgrade not only makes his Haki more powerful, but also unlocks new forms and special abilities: Haki Slash, Haki Cannon, Haki Shield, Haki Avatar...

Rising from the East Blue, Rain crushes every enemy with Haki! East Blue powerhouses? Haki intimidation! Logia users? Haki counters them! Shichibukai? Sent flying with one punch! Four Emperors? A Haki showdown!

He will build a pirate crew strong enough to challenge the Four Emperors, uncover the truth of the world's history, and ultimately become the Pirate King. This is Rain's path to supremacy!

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