User blog comment:Chichiryuushintei/High School DxD BorN Episode 5 Review/@comment-26322543-20150502205721/@comment-26345952-20150502224142

though it wouldn't harm the anime to have Rossewisse early in the story.

plus if next season they decide to make RG official then it would be in a greater scale (if they decide to animate the Sitri vs. Gremory RG)