Zoro told us in Chapter 1032 that he needs to find out King’s race to beat him.
In Chapter 1033 King receives further exposition on his race and what they are about by Queen, who responds to Zoro’s earlier claim that they would defeat the Calamities, rebuts that Zoro has no hope of defeating King, which adds further dread to Zoro’s situation.
The Lunarians were hailed as these gods who could survive in any harsh circumstances, and adapt to them. There’s still more to the Lunarians, as we do not know what exterminated them long ago, but King is a living example of what they are capable of. His ability to survive any condition is in full display as well, as he takes some of Zoro’s most potent attacks like nothing, and even survives a giant explosion he fashioned in order to destroy Zoro completely, while he naturally adapts to it with whatever allows him to.
We saw an interesting panel in Chapter 1033 where Zoro uses Shishi Sonson on King and Zoro says ”Nothing?!” as a reaction to King eating the attack and instantly attacking back.
Now the panel where we see King’s face after the hit is surely a hint from Oda to what is going on with King.
We can see that King went white eyes, so the attack did some sort of damage, but at the same time we see those flames at the exact spot where he got cut.
In the chapter before Zoro mentioned how King is not bleeding despite being hit multiple times by his attacks. – Tho we saw King bleed from Marco’s Kick!
So my idea is that King is using his Fire to close up his wounds and stop the bleeding right after he gets hit, which makes it look like he isn’t taking any damage and that he isn’t even bleeding. Which would work only on cuts and similiar wounds, but not on strong blunt damage, since it would cause internal damage and would cause him to spit blood – which happend with Marco’s kick – , which he obviously can’t stop with his fire.
One other possible hint could be his skin color – now since it’s the manga we can’t see what color it is, but since it’s grey he is most likely gonna have some darker skintone (even tho Oda wasn’t really consistent with that before either, like with Sanji’s siblings hair colors or Queens, which is black in the manga but it’s actualy blonde). Now King could be black, red or whatever, but i think his skin might be burned because he is using his fire to close up his wounds. Maybe he is even missing his nose since he burned himself so much and is now covering himself and his face so people don’t see it.
Some people think King has some kind of Lunarian durablity boost on top of his Ancient Zoan durability, which I don’t think is the case, i think it is a trick – like something i mentioned above. Zoro also said he would need to figure out his ”secret” to defeat him, but if King would be simply durable, how would that help Zoro finding out that he is durable lol? It’s obvious at that point.
Even if Zoro wouldn’t find out that secret that King has Lunarian durability on top of his Ancient Zoan, since he can’t cut him, he needs to use stronger attacks anyways to by pass that durability.
Which is why i think it’s a trick Zoro has to understand and then counter/by pass it.