Talk:Demon/@comment-26116207-20150827185912/@comment-12776-20150828072224

Japanese has at least three unofficial supplement.

This is one using GURPS.

This one use Call of Cthulhu

This one use Sword World 2.0

All are NSFW (but not graphical). Not sure about the first, but the second is hosted on Kurobinega and the third got Kenkou's approval when he comment on it.