These Shadows are probably the ones who cut/hurt him, pair to pair, those who he encountered in his life, I don't think this was a panel meaning that admirals, Big Mom or Mihawk can't fight him, that would be weird.
Although it would be funny to see the reaction of the Fandom in the never ending Mihawk-Shanks fan-feud
It feels like Oda is just bullshitting at this point. Oh Kong Organ doesn't do that much, but Kinemon and Killer do because it's "punches"? Give me a fucking break. Luffy can body the fuck out of those guys. Law no diffed Kin.
Oda's fucking lost it with this shit. Always makes it harder for Luffy for no reason just for plot. Anyone else can hurt him, it's just Luffy can't. He needs penetration Haki. Killer on the other hand doesn't need anything.
Well, we have to see the pictures first, but at the moment I don't understand why a Gear 3rd attack put Kaido down, and an attack way not powerful, even in a combo with Law's and Kid's attack, didn't sort even the same effect.
Mr. Oda isn't a coherent battle-writer, always said he preferes a beautiful story rather a coherent one and ok, that's fine, your manga man. But, here, or Kaido used Haki to defend himself against the combo or Oda just doesn' t care about this aspect.