User blog comment:B214/High School DxD BorN Episode 10 Review/@comment-26268422-20150608231720/@comment-26268422-20150609014428

Yeah, Ddriag all the way ,"possible" is even a stretch. But, I am looking forward to it.

As for "canon"... I do not claim to be absolute on this... but, with the competing versions with the same characters, one has to be designated as the authority. It's only canon if it is in the original source. Even a character that is in the Anime and the Manga but not in the LN would not be part of the "Official" cast. (I do not think there are any... so far.)

Alright... All the above BS aside:  If Ishibumi says it's so then I'm good with it being called canon, no matter the media. So your point is conceded Great Grand Emperor of Red Dragon-san.