yes invent a devil fruit there is only one rule please have fun with this ^_^
rule#1) CANNOT use anything shown from previous one piece series such as crocidiles abilities (the sand sand fruit) or enel's lightning abilties etc. you get the idea. Be creative k.
as for my devil fruit i think maybe a water water fruit…i was going to say wind wind fruit but .... i think luffy's father may have taken it
well enjoyi'm intrested in what devil fruit you'll come up with