Law show his ability at the at first time, and he use this ability to release the slave's bomb necklace too! Of course it's one kinds of Devil fruits but Oda never told us which it is and even
its name. Just guess something about the new ShichibukaiLaw's ROOM ability.
At first we can know that ROOM is a special field and space that under Law's control. He can change everything in this field: cut, consist, mix or anything else. And the one which changed by Law will never injury in this ROOM, but Oda never show us the result of this guys. In Punk Hazard, it's no doubt that the swarrior was seprated by Law and seems that the effect can kep stable at this island. Socond, we can know the measure of ROMM's area not unique, after two years, Law's area become more bigger than two years ago obviously. The last one is whether there are still exist many other ability in this ROOM, Law bring a sword with him and he only used it inside his ROOM, what's the relationship between the sword and ROOM?
Now Smoker has already in the space, he know the ability of Law because he ordered the others escape from the ROOM, but can he overcomed the ability? Maybe his smoke body will never affect here, but nothing is impossible!