We know with strong enough haki one can overwhelm someone else's haki or devil fruit but what if shanks can do something 1 step above
What if shanks can staight up turn off someone's ability to even use their haki and/or devil fruit. Having stronger haki then someone is obviously already a good advantage but if they cant even use their haki or fruit it widens the gap even more
Tho not really canon it was said that shanks was able to stop others from using their observation haki. If that ends up actually happening in the manga it might not be impossible for him to do the same with others armament and conquerors haki
If shanks can just stop someone from using haki while blackbeard can stop someone from using their devil fruit powers it could be a cool parallel between the two
If he's able to stop someone from using both he'd be even more powerful. Also if thats the case it might explain how shanks, roger, and maybe garp are able to compare to characters like whitebeard, sengoku, and the other emperors and admiral. That's assuming they're able to do the same
Back when roger fought whitebeard for straight up 3 days in a row the island was seemingly fine more or less. Possibly because roger was capable of restricting newgates powers
But as soon as whitebeard got angry right after they fought he was able to change the whole terrain around the island
So maybe because of rogers haki powers he was able to fight whitebeard on equal terms. Roger still being the strongest non devil fruit user able to beat anyone devil fruit or not
Whitebeard still being overall still considered the world stronger man because of his devil fruit on top of being able to compete with roger without it. Making both roger = newgate and newgate = the world's strongest man true