User blog comment:SpookyBoogie27/Light Novel Spoilers/@comment-115.133.205.1-20130219144240/@comment-1359322-20130220025520

Well who knows maybe the author might even write 2 Extra Life, one on Yuuto's past and his trip to Romania with Rias and Azazel, the other one on Issei's side after his battle against Grendel. Well the author did mentioned in his blog that the next short story will be about a girl who formed a pact with a legendary Dragon and took place between Volume 14.