During the current chapter 905, we got the introduction of Ryokugyu, he is not fully shown, just shadowed. We yet can’t tell much about him, he seems to be male, he has the same body-type as Fujitora and…he is fasting!
As we know people in Elbaf used to feast for religious purpose.
Now we can’t clearly say if Ryokugyu comes from Elbaf because of his body-size which is similair to Fujitora…but what about his devil fruit?
It is well possible that he is a kind of higher-tier Zoan fruit.
Fujitora is Paramecia, Kizaru is Logia… Oda could complete a set here.
Green is the color of fertility, life but also mystery and mythic.
Ryokugyu possessing a fruit that shapes his body as he pleases could open the possibility for him being a giant from Elbaf (probably sold by Mother Carmel).
I believe it’s possible, that he has the mythical Zoan “Shapeshifter”.
Shapeshifters are mythical creatures, mostly demons, fairies or enhanced living beings, like Vampires or Were-animals.
There are dozens of variants and mythical named Shapeshifters, it doesn’t matter which one Ryokugyu is, Oda could create his own Shapeshifter at this point.
But for animals it most likely seems that animals appear naturally, but they can instantly change into their shaped demon-form-like, for example if they attack. Oda could foreplay the bull-theme shapeshifting with this. Like an animal who is waiting for his ambush, similar to Shapeshifters.
*Theory by Rej Discussions