User blog comment:Crimson and Darkness/Volume 24 discussion blog/@comment-31.11.130.118-20171221162440/@comment-2A02:8109:10BF:B444:0:0:0:2-20171223112459

ExE is the Power that is locked inside Issei and AxA is the Power of all 3 (4) together!

So what could mean ExE and AxA ? I would say ExE is something with Eternal and AxA with Apocalypse.