One Piece: Awakening the Zanpakuto System and Clashing with Kaido

[Ding! The strongest Zanpakuto System is at your service.]

After transmigrating to the world of One Piece, he awakens the strongest Zanpakuto System.

Draws a Bankai ability from the start...

[Ding! Emergency mission: A drunk Kaido has arrived. Kaido is itching for a fight.]

Host, please complete the mission as soon as possible... or face the consequences.

“Hey! This isn't the kind of mission I wanted...!”

“What a rotten System! What a rotten world!”

Transmigration + System + anime-style snark + one heroine [Yamato] (no joining the crew, no enlisting in the Navy)