User blog comment:Stbk22/Possible power up/Techniques 2 for New Arc/@comment-1884090-20160804155912/@comment-1359322-20160805001831

Well Rias currently has Valerie on her side, so mastering the Extinguisher Star shouldn't be impossible. Same goes to Akeno and Koneko. I'm sure Valerie will be able to use her Sephiroth Graal to enhance them to an extent.