Speculations It's time to say goodbye to Sandai Kitetsu.

Because i believe that the final grade of a Black Sword depends on the Wielder's Haki level.

If Mihawk forged Shusui into a Kokuto, it would be a Supreme Grade Blade.
If Ryuma forged Yoru into a Kokuto, it would still be a Great Grade Blade.
Yea I don't believe Mihawk is stronger than Prime Ryuma in anyway.
Don't know why still the obsesion didn't he left wano with it,when nidai was there?the only grade sword that left is shodai kitetsu but I even doubt he will get it
Zoro got 3 swords from 1 gurl and 2 woman.
Only one way for Zoro to get a new sword is if a forth woman give him another but I doubt Oda will write that.

No wonder the swords that were gifted by men got shattered, rusted or given back too and subplot dropped.