One of the Inazuma Eleven games had a superboss that was the spirit of a king that died before the beginning of the story. When you battle him he takes the form of a shota with the excuse that spirits take on a youthful appearance.

I find it kind of humorous they went out of their way to make sure an adult wouldn't ruin the magical shota soccer game even though there have been a few adult players in the games before.