Without the fruit? The whole reason why he got the fruit was so that he could show all of the other Devil Fruit users that their powers would be useless.
In other words I'm trying to say that he knew that he would have to fight many people with Devil Fruits in order to become king, includion Logia's who can't be hurt physically. So he sought out the fruit that would nullify that barrier so he could get in and pummel them like he always does.
So the reason why he got the Darkness Fruit was so that he could bypass people hiding behind Devil Fruit powers and show them what pain is. More or less.