Ryuo is still "just" the name of Haki in Wa No, it is not the name for the penetrating Haki, it just means Haki.
Later Hyo mentions that outflowing Haki (which is first advanced form if you wanna call it that) is an application(synonym for technique really) of Ryou.
Penetrating Haki/Ryuo is even one step further
So it´s invisible CoA in your body/on skin < Koka < outside/barrier Haki < barrier penetrating Haki.
And it is the second advanced level of CoA you need if you want to hurt Kaidou physically (hax and elemental damage would still work i presume). That´s why when Kaidou says "you know the same Ryuo as Oden" to the scabbards, he means penetrating.
The question is, and we do not have yet an answer, is the amount of damage you can do with penetrating Haki only limited by the amount and strength of the Haki itself, or is it, just like normal CoA, a combination of your Haki level and your attack power otherwise.
I would suggest the latter.
It's not advanced CoA lvl 2 tho. The quirk of advCoA lvl2 is, that the impact of someone's haki is shifted away from the point of release. Within that gap this lvl2 type skips through the "outer" durabilities of objects and opponents.
Just look at the tree scene with Luffy. On Luffy's side the outer bark of the tree is still there and completely undamaged, while the inside is completely blown away.
It's the complete opposite of what's happening now with Kaido.
They actually stab and cut THROUGH his skin/his body.
It's advCoA lvl1, simply haki infused sword swings and slashes.
And for the thread:
This is still so weird. If this is really not a) a inherited will thing or b) something along the lines of "feelings of revenge pushed their haki beyond their limits" - thing, then Kaido's hype just got "shattered" by "normal" advCoAlvl1 users and it's what he refers to with "Oden's haki".
A guy like Raisin is able to do exactly that btw aswell. I know well that it's a skill based concept and stronger characters can pull out higher levels of power with the same tech, BUT still, where do you draw the line there?
I start to think that perhaps we are all just in denial and that haki infused weapons are rarer than I/ we had thought.
Nearly all of the people who made use of it, came from three major factions: Wano, Amazon Lilly and the marines. Coincidence?
None of the BM pirates besides Raisin showed it for example, not even Kuri on Mogura. Hmm.. Someone like Vista for example has it confirmed, but unsurprisingly he's also specialized in swordsmanship.
It would do very well for Smoker, Vergo, Zoro, Boa Hancock, Sentomaru and Kinemon himself though. And it would support my idea that the AP from Zoro and something like Oni Take stems from superior haki usage and not primarily from physical stats.
And btw, pretty sure that in general all that "can't kill that thing hype" about Kaido is now meant for his awakened Form. Oda can't really just specify it, without including major Spoilers. No way that's all there is to Kaido.