Daddy chill.
This is a katana, until it is proven that it isn't.
This is a walking stick until it is proven that it isn't.
This is a toy until it is proven that it isn't.
Just because a sword looks black it doesn't mean it is the same thing as Yoru and Shusui.
It could be but also not. That is why a direct statement in manga is needed to confirm/disprove it.