Roronoa's Devil Fruit - the (Sleep Sleep) Fruit
So, I was thinking about what devil fruit would Roronoa get, and I've come to the realization that the hypothetical Sleep Sleep fruit would be the best kind of a fruit for him.
Now, the Sleep Sleep fruit is very unique and it would match his style really well.
The way the fruit would work is, whenever Roro is asleep that is when his fruit is active, he will be completely immune to all physical as well as non-physical attacks. Basically, while he's asleep he would be completely outside of the effects of time and space; so nothing, not even a thought would be able to hurt him.
While in sleep he would be going through everything the crew is going through but in a virtual world mimicking what's happening in real-time. So he would gain all the experience and talents while asleep and learn new stuff, too. Just as if he were actually with the crew.
Now, when awakened from sleep, he would not have any of the weaknesses of a typical devil fruit, "sea water/stone."
So, when he's up, he can swim in sea water and dive without being affected by it, like let's say Luffy would.
Basically, his Sleep Sleep fruit would act outside of time and space when he's asleep, like a virtual world/augmented reality that's simulating what's happening exactly in the real world in real time, and when awake none of the typical devil fruit user weaknesses would be affecting him.
Pretty sick, eh?