User blog comment:Vamsisonu/AWESOME/@comment-4681125-20120319105543/@comment-3507136-20120319111811

Actually the answer to the first question is a sort of. We have limits, you cannot create a Yonko because there are already four, same goes for Shikibukai, Admirals, Fleet Admiral, All above fleet admiral You are somewhat limited, but not by much. Devil Fruit wise you can, as long as it's not already taken and it isn't in the canon/non canon.

Too answer your second question, also sort of. This wiki is a place to create your own character's, not just copy another anime's and bring them to here. . . it's just no fun. Make your own character and have fun, your allowed to use other characters images, but none already taken.