K: I see... Do you want to be a king?
Z: Ah?
L: The world's strongest swordsman? That's great! The pirate king's nakama would need to be that strong, or I'd be in trouble!
Z: That's right... I promised my captain, and my dear friend!
I think probably if you're Kozaburo and made Enma, even a fairly decent sword by regular standards would be considered blunt. At least that's what I interpreted.