There are so many unknowns about Haki. There are question we don’t we even know yet to ask, because (G)Oda still hasn’t fully explained the full extent to which Haki can effect people or surrounding.
Before Kaido was hurt by the Red Scabbards he had a flashback to Oden’s execution about him not dying and his will living on. Then we see the Scabbards inflicting wounds to Kaido.
At that exact same moment on the next page we see Kaido reacting to the wound Oden gave him and then questioning himself if the Scabbards are using Oden’s Haki.
My point
We can’t neglect the fact that Haki can last centuries if it’s strong enough. Just like the black blades and Ponegylphs. Oden’s will was so strong that he left residual Haki on Kaido and when met with the Haki of the Red Scabbards (Oden’s Retainers/Family), it activated in response giving the opportunity to hurt Kaido.
This might not be related anyway Shanks noted that the scars over his left eye were currently aching and revealed that Blackbeard inflicted them before describing how Blackbeard deliberately avoided becoming notorious during his time on Whitebeard’s crew.
Shanks warned Whitebeard that Blackbeard would come for his position now that he had gained strength and started moving, and when Whitebeard asked him what he wanted him to do, Shanks asked him to stop Ace because he felt it was not the time for he and Blackbeard to fight.
I believe this is the first time that we see that Haki can be left on a person. This would make sense because Shanks was basically saying that Blackbeard’s Haki was strong enough to face Whitebeard and Ace wasn’t on that level yet to face Blackbeard, based on his own personal experience.
Keep in mind this is just brain storming off my own logic and understanding and nothing is concrete. I could have hit the mark or missed it by a mile.
*Theory by Jblaz3215
