Sailing: I Open Treasure Chests in the Pirate World

Upon traversing the world of One Piece, Ian obtained a god-level treasure chest system.
The system treasure chest can help Ian obtain what he desires most in his heart.
The level of the system treasure chest can be used to enhance Ian's own abilities.
There's only one way to get the system treasure chest—fight!
The stronger the opponent and the more intense the battle, the higher the level of the system treasure chest Ian can obtain!
Thus, Ian, who grew stronger with each battle, made the entire pirate world tremble!
Blackbeard: "Why! Why do I have to live in the same era as a monster like Ian?"
Whitebeard: "This kid is terrifying! I really am a remnant of the old era!"
The Five Elders: "This Ian is even more terrifying than Rocks was back then! Does he intend to overturn the entire Red Line?!"