User blog comment:B214/Volume 17 spoilers./@comment-1359322-20140311050948/@comment-24468758-20140311063534

Regarding more volumes for Rias and Akeno I hope so too. Furthermore the date with Le Fay could be a hint on a volume for her.

Kiba really should raise a flag with Tsubaki already, but a power-up regarding him sure is coming since this time Issei is improving DWF and achieving Longinus Smasher and Kiba is the one who fights alongside Issei the most so he needs to improve quite as much as Issei.