@unnaturalsolace I think that it might just be a mistranslation by the scan crew, the “green” oni’s name is Ao, which is probably short for Aoi or 青い, which is Japanese for blue. Ao is also used in descriptive words so aosora or 蒼空 is blue sky. You are right though, it was originally red and blue. The red oni’s name (aka) is also just a shortened version of the word red.
@-TT- Oh no, I wasn't complaining! I was just trying to help clear confusion ^^ it was not my intention to make the scan group feel as if they had to correct anything I was just trying to help.