After seeing a silhouette of what seems to be Orochi's true form in chapter 927 I think its fair to assume he has a devil fruit. Would you think a mythical/ancient Zoan is likely? Let's talk about some ideas for a multi-headed beast and possible powers.
As soon as I saw the silhouette, Hydra came to my mind. Let me convince you why this would be a great devil fruit for Orochi. First of some mythology. Hydra is a multi-headed serpentine monster in Greek and Roman mythology. It has regenerative abilities and breaths poison. In the myth of Hercules's Twelve Labors, whenever Hercules cut one of Hydra's heads two more would regrow. Hercules had to cut all of Hydra's heads and burn the necks with fire to kill it. That would make Orochi a Mythical Zoan (Hebi Hebi no Mi: Model Hydra?) Devil Fruit user. I don't know about the poison ability, but regenerative abilities sound great, especially considering Zoro will probably face off with him. Imagine Orochi in a hybrid form in which he can use his Two-Sword style and regenerate limbs if Zoro cut them off. I hope I'm right because that would make for an awesome fight. Zoro would have to think out of the box and maybe show us or develop a new technique to win against such a devil fruit.
But still I might be completely off and Oda is going for something completely different. Give me some feedback and ideas you may have. I;m pumped to see Orochi next chapter.