https://worstgen.alwaysdata.net/forum/threads/what-is-ryokugyus-hair-color.30605/#post-4574332
Unfortunately, Ryokugyu will have green hair.
I had already feared it for a long time and I had even made a topic where I talked about this little fear.
Some people laughed at me a little, but I already knew that there was a good chance that Ryokugyu would have green hair.
Honestly, I'd even have preferred to be wrong at the time and prove the people who took me for a moron right 😅
You could see that Oda was fed up with drawing characters with black hair and wanted to give a different design to these characters who would normally have had black hair (Queen, Page One, Orochi, Katakuri, Oven and now Ryokugyu).
I really wish Ryokugyu hadn't been different from the other admirals in this respect. I mean, even Momousagi and Tokikake have black hair... Such a shame.