In the latest chapter we are given some new information (or just affirmation to already known info) about Haki.
Although I think this is absolutely a fact now, many people misunderstand what it means. Yes, Devil Fruits can be countered with stronger Haki, but I don’t think just having stronger Haki automatically nullifies Devil Fruits, since Law was affected and turned into a woman even when he has strong Haki.
I think you need to Actively use Haki to guard from Devil Fruits, like maybe coating yourself in Haki. This also gives credence to the theory that Kaido and Big Mom are coated in Haki 24/7, that’s why they are so durable. And when Mother Caramel’s portrait breaks, Big Mom’s will goes down and that’s when she can be hurt. And Law couldn’t use Shambles on Big Mom and Kaido since they are always clad in Haki, possibly Conqueror’s Haki coating.
Now the question arises, but what about Sugar? Does she have stronger Haki than Chinjao, Cavendish, Sai, etc.. since her abilities worked on them and they could not negate it?
Actually it’s a pretty simple answer. Like i said earlier, just having stroger haki doesn’t negate Devil Fruits abilities. They just didn’t know about this. It took Law a fight against a Yonko to realize that Devil Fruits abilities can be countered by stronger Haki. So I think it’s fair to assume that these people simply lacked the information to do that and did not try to counter it with Haki.
In Sugar’s case, she can take away free will unless you have the information before so that her Devil Fruit’s effects can be nullified with strong Haki and you can actively defend against it. But if she touches you and you didn’t know this, you’re gonna get turned into a toy and lose your free will (No Will = No Haki), then there is nothing you can do.
I think yoy can only nullify the Devil Fruit effects that are directly affecting your body. Also I think Awakenings cannot be nullified.
*Theory by MonkeyMassiveDLuffy