User blog comment:Chichiryuushintei/High School DxD BorN Episode 5 Review/@comment-3965848-20150504112223/@comment-1359322-20150504134509

Since it's High School DxD, I'd say up to 3rd year only, in short till Ise graduates from High School. Probably by the time Issei graduate, Rias would have start her career at the Rating Games and Head of Gremory already. Probably won't be active as a DxD member anymore.