User blog comment:B214/High School DxD EX/@comment-1359322-20150913235748/@comment-181.104.96.73-20150917155937

I belive EX takes place post-V18 and pre-V19 because it has mentions to irina having a holy sword and not a holy-demonic sword and it also mentions the kasha tecnique and it wouldn't affect history if by the end of the story everyone recieved a memory wipe so as not to alter the future.