Talk:Rou/@comment-208.169.90.206-20150524224314/@comment-98.221.3.160-20150525215619

I think this is a quirk of the Japanese language and the author.

It seems like "oni" is used as the general family name for any species that evolves out of goblins. In English, we normally translate that as ogre, but the implication for the entire "family" is that they are demons. Daioni, or great ogre, is a third evolutionary step for the demon species. What's more, the author seems to use the word "oga" for the third step which is just a Japanization of the word ogre.

In other words, it's something that's more clear in Japanese, but only because the author is mixing a lot of terms for similar things from different languages, that people have been translating for convenient reading into a single language, the end result being a few mixed implications. Basically, don't worry about it too much.