One Piece's Master Swordsman: Teaching Swordsmanship Makes Me Stronger

After transmigrating to the world of One Piece, Leon awakened the Ghost Hand and changed class to become GSD, a mentor to Ghost Slayers.

As long as his apprentices who changed class to become Ghost Slayers grew stronger, Leon could become infinitely powerful!

…

[Apprentice Akin (Berserker) has grown stronger. You have obtained Conqueror’s Haki.]

[Apprentice Zoro (Sword Shadow) has grown stronger. You have obtained the bloodline of a yokai, the Lord of All Evils.]

[Apprentice Issho (Asura) has grown stronger. You have obtained a Ghost Slayer’s First Awakening Stone.]

Leon: “If you don’t work hard, how am I supposed to become the world’s strongest swordsman?!”

…

This book is also known as: “One Piece: Those Who Don’t Work Hard Enough Don’t Deserve to Be Ghost Slayers!”, “In One Piece, I Make Everyone Work 996,” and “One Piece: I’m the World’s Greatest Mentor!”