Ryuou I think is the same thing as "Haki" it's just Wano's cultural name for Haki just like Skypiea's cultural name for Haki was Mantra. I mean we even had Luffy make reference to Hyou's haki with Ray, Sentomaru and Boa's sister. So that alone is proof that they are the same concept.
Fact that Kiku and Kin (and most likely all of the scabbards) were able to hurt Kaidou is proof that they have both acquired an advanced stage of Armament Haki akin to what Oden used to hurt Kaidou 20 years. I mean Kaidou literally said so himself. So in short they are advanced Ryou/Haki users. Most likely using the same penetration Haki Luffy has just learnt on Udon.
Note as well, that one of Boa's sisters was capable of using Barrier haki even though she is relatively weak by today's standards so I guess the scabbards being able to use it isn't that surprising.
Fact that Kiku and Kin (and most likely all of the scabbards) were able to hurt Kaidou is proof that they have both acquired an advanced stage of Armament Haki akin to what Oden used to hurt Kaidou 20 years. I mean Kaidou literally said so himself. So in short they are advanced Ryou/Haki users. Most likely using the same penetration Haki Luffy has just learnt on Udon.
Note as well, that one of Boa's sisters was capable of using Barrier haki even though she is relatively weak by today's standards so I guess the scabbards being able to use it isn't that surprising.
