User blog comment:B214/High School DxD Hero Discussion/@comment-3965848-20180507203312

I could be wrong but I think V9 saga might end on ep 5, leaving ep 6 open for a possible side story adaptation.

Reason: epi 4 adapts the reminder of Life. 3 and primarily Life. 4, while epi 5 will cover what's left of it.

If so I'm thinking it's Student Council's Decision.