Aside from Supreme Great Swords, of which there might truly be only twelve, weapons of the Great Grade Blade tier actually numbered far more than twenty-one.
The term Twenty-One Great Swords referred to the twenty-one Great Grade Blades listed in the catalog, all of which were heirloom-grade treasures standing at the pinnacle among weapons of their class.
Moreover, the Twelve Supreme Great Swords, the Twenty-One Great Swords, and the Fifty Skillful Grade Blades were all ancient rankings passed down from a long-ago era.
Naturally, many powerful weapons had emerged in more recent times. Some were not even inferior to the legendary Supreme Great Swords, but later generations could hardly alter the old rankings, which was why terms such as famous blades and famous swords came into use.
For instance, Golden Lion's Sakura Jyu and Kareki, Red-Haired's Griffin, and Gion's Konpira were mostly sharper than Great Grade Blades but below Supreme Great Swords, and thus were called famous blades or famous swords.
This showed that just because Zoro's beginner equipment was one of the Twenty-One Great Swords, one should not assume weapons of that tier were worthless. In truth, any Great Grade Blade listed in the weapon catalog could stir up a storm across the seas and drive swordsmen into a frenzy.
And as the renowned Land of Samurai, land of craftsmen, and land of swordsmen, any of the Twenty-One Great Swords that emerged from Wano Country would absolutely incite upheaval across the seas.
As for why Eric had such information, the reason was actually very simple.
From the memories Apophis had read, Eric had originally been a swordsman of Wano Country. He was a product of Kozuki Oden's resistance against the closed-border decree and, in a sense, could be considered a contingency Kozuki Oden had left behind before returning to