The World Government has deemed the distribution and consumtion of Devil Fruits limited to only the Marines. Making the distribution and consumtion of Devil Fruits completely illegal outside of the Marine force. The World Government has done so due to the fact that they have deemed such fruits as lethal weapons of mass destruction and are maintained. Despite the law, a number of Pirates have gotten their hands on Devil Fruits which are infact quite rare, but anyone other then a Marine who has consumed a Devil Fruit has an automatic bounty of 1,000 and will be pursued till incarserated.
A nationally concesus is taken of each Devil Fruit in the world and those who have consumed them. You are permitted to have your own Devil Fruit but it must be over viewed to make sure it has potential to begin out well balanced and then become gradually more powerful