I just came across a theory if Roger had a devil fruit and what the Devil Fruit might be. Firstly there have been very interesting evidence and suggestions that Roger did not have any Devil Fruit such as the time with Buggy and Shanks as new member of pirate kings crew had little to no idea about Devil Fruits and also it seems that Roger had wooden and not seastone cuffs at the time of execution. But to counter there have also been strong indications if he had a DF such as the time when he was talking to Garp to help him with his kid he lit up the torch and the time when he faced Shiki. 1) So the lighting of torch indicates a strong possibility of him having the Mera Mera Nomi. Which also makes sense since Ace got this fruit being a newbie (Logias are rare and we have seen this type of DF with people as strong as the Admirals) 2) Since Shanks was carrying the Gomu Gomu Nomi with him it is possible that Straw wasn't the only thing Shanks was carrying with him which belonged to the PK. Since it is widely considered that luffy inherits Rogers will, it is quite possible that he might also be carrying his DF. But to how possible this might look there have been no reactions from the people who have fought Roger in the past seeing luffy use it. 3) But the craziest of all the possibility that Roger may have had the DF that Dragon is using right now which could possibly be Wind Logia/ Paramecia or mythical zoan Dragon based on what we have seen with the manipulation in weather Dragon does wherever he went. Now this could have happened due to 2 reasons A) Since people like Doflamingo, Caesar and few others who knows what happens to the DF once a DF user dies it is very much possible Dragon knew it too, being an excellent strategist, being the most wanted man, and a former Admiral must have accounted for access such type of information. Anyways he planned to get the Devil Fruit at the time of his execution and hence he was present there. He had no tattoos back then too which suggests that RA was not formed back then but that's how he got the DF and in some period of time he might have fought Akainu where the WG learned that Dragon had Roger fruit and hence increasing his bounty and making him the most wanted man B) Dragon was an Admiral at the time of Rogers execution and the WG Dragon the fruit but later on Dragon learned something of WG may be the National Treasure of Mary joise leading to him turning against the Celestial dragons and hence becoming the world's most wanted man. Not my theory but I had some ideas of my own and wanted to share, Thanks for reading and share you opinion on this.