The first three admirals were inspired by the legend of Momotaro as follows:
•Kizaru- Yellow Monkey- yellow the colour of light and monkey for his irresponsible personality
•Akainu- Red Dog- red for the power of magma and dog for him being loyal but persistent
•The new admiral Fujitora- Purple Tiger- purple the colour of his gravity attacks and tiger for his fierce character
Also we see a major change in the power theme with Fujitora changing from a Logia to a Paramecia and this implies a great consequence for Ryokugyu’s new power. There are two famous speculations. It either goes to the science theme or to the three fruits theme.By the above logic:
•Ryokugyu- Green Bull- green for his power(also aestheticaly even the colouring of his attacks like in Fujitora’s case) and Bull for his personality as a hotheaded guy.
As we all know the colour green in japanese culture but even abroad is asociated with nature, fertility, youth, vitality. Also the colour green in japanese is midori which means vegetation.
Now, we must get something clear: if the power goes by the science theme it would be a paramecia or logia, I believe, but the zoan theory seems more plausible for me because it completes the new trio and it also gives a sort of equilibrum because we haven’t seen such a strong guy in the marines that has a zoan type so I’m going with this hypothesis. Now, if he bears a zoan type fruit there is a slight change in the meaning different of the other admirals. If he is a zoan he should fall in the class of bovines as his monkier suggests because you can’t nickname him Green Bull and give him another animal type; it just wouldn’t make any sense. Thereby I got two versions of his zoan type fruit:
1- Ushi Ushi no Mi, Model: AurochsThe aurochs is a famous extint type of wild cattle and is the ancestor of domestic cattle which was extincted around 1627. He had an average height at the shoulders of 155-180cm in bulls and 135-155cm in cows, with horns at 80cm length and 20 cm girth. He was much heavier and bulker than the modern cattle with long athletic legs and strong leg and neck muscles.
Now this goes for the standart bovine zoan he might have and the fact it’s ancient zoan makes its raw strength and physical power quite formidable.
2- Ushi Ushi no Mi, Model: HakutakuThe Bai Ze, or as it is known in Japan, hakutaku is a mythical creature with a bovine body with nine eyes and six horns arranged in set of three and which is quite knowledgable and intelligent. Also in one account it once appeared in Mount Tateyama and predicted that a deadly plague would sweep through in the next few years and prescribed that its own image be used as a talisman to ward off the disease, and since then the hakutaku has been worshiped as a guardian spirit of herbal medicine.
Now this brings us to the analysis we made at the beginning that his powert will be themed after the colour green and how this colour correlates to vegetation and growth, virility. Since he got the power of the hakutaku he might be able to grow trees with healing powers, use nature based attacks except for his strength granted by his bovine nature. He might also “eat diseases” (as in the myth of the Bai Ze) or cure himself and on top of that he might even be a doctor in the marines by profession.
Hope you enjoyed!