My speculation: I don’t think Katakuri used haki to predict moves and change his body to avoid haki attacks. I believe it all comes down to the unique properties of his devil fruit. I’ll explain.
I think the best way to explain it is to first talk about seastone, haki, and blackbeard’s power on devil fruit users, specifically logia, paramecia, and now special paramecia.
Let’s pretend Blackbeard is fighting Sabo for some reason, now a logia user. Consider these three scenarios:
1) If Blackbeard threw Sabo into the ocean or hit him with seastone, Sabo WOULD feel weakness, but he COULD still use his powers. But, his entire body is affected.
***Note: The affects of seastone actually range, depending on the density used (see WIKI page)
2) If Blackbeard tried to grab Sabo w/ haki, he could touch him, but Sabo WOULD NOT feel any weakness. This is b/c it allows you to touch their “substantial body.” Only the spot being touched is tangible. Additionally, he COULD still use his fire. This is b/c you’re basically able to touch fire while it still REMAINS fire (if that makes sense…you aren’t changing fire’s properties except it is now tangible).
3) If Blackbeard grabbed Sabo w/ his darkness powers he (similar to haki) WOULD NOT feel weakness, but (dissimilar to haki) he COULD NOT use his fire powers. His entire body is affected. In that moment, he is essentially no longer fire.
Again, above fight is just an example for clarity–not a prediction.
The reason this explains Katakuri is that when taking haki punches from luffy, those blows are landing, but haki doesn’t take away his state of being mochi. The reason why they pass through him is that mochi is far less elastic than rubber. It’s stretchier, but less elastic.
It’s essentially chewing gum, so you can poke holes through it and it’s fine. Like, if you play with your gum after stretching it and putting holes in it, you can keep messing with it until it comes back together. Good as new!
It’s stickiness and pliability are what allow this. The reason why it doesn’t work for Luffy is that rubber is, while more elastic than mochi, less stretchy (AKA more rigid). We can see this play out when Luffy takes bullets. His body naturally resists the change in shape being induced by the bullets, which is why we get such a strong recoil.
Elasticity is an object’s inclination to return to its original shape, while pliability or stretchiness is an objects inclination/readiness for change in shape. We can notice the importance of recoil/elasticity when Luffy performs his more powerful moves.
While sometimes Luffy just throws his arm, stretching it to punch without using the recoil of an already stretched arm, it’s generally done for weaker/regular moves like gum-gum pistol. However, when using his more potent attacks, he almost without exception makes use of rubber’s elasticity–being sure to throw back his limb(s) first. The lesser elasticity and increased stretchiness of mochi also explains why Katakuri just throws his attacks forward w/out first throwing them back.
Now, back to haki. Just to reiterate, haki ONLY allows contact with the devil fruit user. It doesn’t make the recipient feel weaker or lose their devil fruit ability. They retain all of their fruit’s properties w/ the exception of intangibility. In that area of contact (at the risk of being redundant) they can now be touched. As a paramecia user, Katakuri can be touched (w/ or w/out haki) but his body is more ready to change shape than rubber. Again, this is why quick and or forceful hits ultimately could pass through him. He was still mochi.
Wait, then doesn’t that mean Sabo or Ceasar could have haki punches pass through them? They should still retain their gas/flame properties. Why did Ceasar still get damaged by Luffy?
Being able to play with gum and make it new again is a property unique to mochi. That isn’t something gas does. Gas is FLUID, the property of moving around objects or filling a container. It’s essentially the property of being INTANGIBLE. If we’re saying luffy can keep a hold of his opponent while using haki, that’s b/c the gas isn’t allowed to move out of the way. Your punches keep making contact. So the gas fruit is the same scenario as fire with Sabo I mentioned earlier. It keeps all of it’s gas properties, EXCEPT it’s now tangible.
But, if there’s contact in the blows, why is Katakuri unscathed by the attacks?
Again, this is because, like bubble gum, mochi can be put back together after being torn apart. I’ll try using another example. It’s a lot like Marco’s devil fruit. Marco feels the pain, but his body heals (in this case due to his phoenix flames). Katakuri does this too, by annealing himself back together. So it definitely still hurts, but it’s repairable. While the panels make it unclear, this point can be further driven when considering the attack Ichiji landed in his quick exchange w/ Katakuri.
While we don’t know if Ichiji imbued his punch with haki (that would be relevant, as he would be more or less likely to stick to Katakuri) we can see it clearly exploded. If we still held the opinion that Katakuri predicted his move and adjusted his body accordingly…things get complicated. We would have seen his body fly everywhere in order to accommodate the blast radius.
It’s far simpler to assume Ichigi managed to blow his body apart, but Katakuri reassembled himself. The panels almost make it look as if his top and bottom half were completed separated. As a paramecia, this would normally be a mortal injury. But, for Katakuri, it’s no problem at all. He can simply stick himself back together.
This also explains why Katakuri felt the need to block Luffy’s punch with his own. If he knew what Luffy was going to do, why block the punch at all? Why not let the punch pass through him like all the others? It’s because it hurts! He chose to use haki as to match Luffy and to prevent red hawk from going threw his arm (rubber is less compliant than mochi).
So why is he called a “special” paramecia? Why were we introduced to him as a logia?
Katakuri can produce motchi. My interpretation is that he’s either breaking off pieces of himself or he’s using awakening (Oda hasn’t shown us yet). That combined with his ability to take blows is why Jimbe referred to him as a logia. So he’s a paramecia, but he’s FUNCTIONALLY the same as a logia.
In conclusion, any devil fruit user who is hit by haki is tangible (at that location of contact). While this isn’t the only possibility that checks out, it makes sense and seems pretty sound to me. I’ll end with a joke a made in the chat. We put a lot of thought into our speculations, trying to remain both logical and thorough. But for all we know, Oda could change everything we cook up and say…
“Haki is attacking with your spirit, so if you attack someone with haki, you’re attacking their spirit….their ‘substatial self’!” ….lol
*Theory by TwinKidd_B