User blog comment:Jopjopjop/Volume 19 Spoilers/@comment-25635127-20141115033208/@comment-1359322-20141115040322

Well we'll have to see how long Ishibumi intends to go with the fifth arc. The fourth arc is used to focus on characters Ishibumi hasn't given a volume on like Xenovia, Irina and Gasper. Another purpose of the fourth arc is to allow Ise move to his third year and for Rias to graduate.

Come to think of it, when Ishibumi said he was going to do another Volume for the main 4 girls, i was initially thinking "again, come on do they have anything to further expand on?" But now i think it's a great idea. For Rias and Akeno's volume, Ishibumi could focus on Rias and Akeno's college life. For Asia, it's her current status as ORC president. Koneko, i believe we'll have our answers soon.