Please don't add too many characters not in Canon. You add too many OP character not from DxD that it had become a completely different story with DxD elements instead of a fan-fic. What the use of DxD characters when countless figures more powerful that Great Red appears?
Used too much original characters destroy fanfic story, it's been proven by soo many failure fanfic in chinese qidian.
Moreover, rather than infodump us with this revelation better put it in later part of story where Jason strong enough in DxD world and his current 'parents' told him all of this sh*t plot.
"GAE... BOLG!!!!!" Spear racing toward its target... "I am the bone of my sword... Rho AIAS!!!!" I replayed that video I don't know how many times on Youtube
RekiChan