Garbled Japanese mythology: what could a "ryuku doji" be?

Factual Questions
1

I’m playing a mobile game that has characters from mythologies of different cultures. One is a “ryuku doji”, which looks like a cute boy with a turtle on his head like a hat and carrying a glowing ball in one hand. From the name and the character’s clothing, I’m pretty sure he’s meant to be Japanese.

All of the other mythological characters in the game seem to actually exist, so I’m assuming this one does too. I think this spirit/god/whatever is cute and I’d like to know more about him, but he doesn’t sound familiar to me at all. I’ve tried Googling every variation on “ryuku doji” I can think of, with no relevant results, and searches like “Japanese spirit turtle” just get me stories about kappa. The developer is I think Chinese, so I’m guessing they got something wrong in romanizing the name (or maybe this beastie is just super-obscure and has no discussion in the Google-indexed part of the English-speaking web).

Thoughts from the great minds of the Dope?

2

So, doji means mistake. ryOku means power, and ryukYu is a set of islands, and also an Okinawan endangered turtle called the “ryukyu” turtle. Maybe a pun or sloppy translation?

3

“dōji” with the long o, or 童子、is a somewhat archaic word meaning boy or child.

As Lasciel said, Ryukyu is the old term for the Okinawa area, as well as being the name of the kingdom that ruled the area until the 19th century.

Ryugu or Ryūgū-jō is a mythical undersea palace. Probably the best known appearance is in the Urashima Taro story.

4

p.s. There is actually a tale of the Ryūgū Dōji (竜宮童子）, a boy from the Ryūgū palace with special powers. Here’s the Japanese Wikipedia entry, if you want to try feeding it to Google Translate.

5

Thanks! That looks like it is probably it, with the turtle hat maybe being a reference to the turtle species Lasciel mentioned? The greatness of the Dope validated once more!

Anyway, I commend the creators of this game for including some very obscure folkloric characters (when was the last time you heard about Empusa?)!

6

Google images (the Japanese version) shows him riding a turtle and holding a ball (sometimes a box).

I hadn’t heard of this tale, but the underwater palace also features in Urashima Taro and there the turtle is the principal method of transportation between the palace and land. Presumably, that’s where the turtle comes into it.

The boy grants wishes in the story. I would assume that the ball is what he uses to do this. The Wikipedia description doesn’t mention such a thing, so it could just be a bit of symbolism thrown into the drawings to indicate that he has magic. Not sure.

If there’s any jokes about him stinking to high heaven, then that would be a definitive confirmation that this is who the game character is. But the name and description are so close that I don’t think there’s any doubt that scr4 got it.