The main strength of this Devil Fruit is that it allows the user to generate and manipulate liquid metal.
Graydle is able to split himself into many communicating parts, which can take the form of himself or others. As such, he is able to impersonate groups of humans, such as Marine soldiers and dogs. To search large areas in urban environments, Graydle also uses the fruit the make a prosthetic arm for himself, which he can make bigger or turn into a blade.
Aside from the standard Devil Fruit weaknesses, there seem to be no known weaknesses to this power.
Graydle uses his abilities to create clones of Zoro, Sanji, Chopper,Nami and himself out of metal to fight for him. He also transformed into a group of Marine soldiers and dogs, and used his abilities to make himself a prostehtic arm.