Thread:B214/@comment-24605349-20150713154325

I think that they used Loki's curse as trigger for the JD, just think about this points:

1) Loki's curse worked in the deep of Issei's and Rias's heart manipulating them for destroy them

2) while in the imperfect JD Issei is "tortured" by Raynare's Ghost, if we can call like this (1° point to Loki's curse as trigger)

3) Vali and Ophis while looking Issei's imperfect JD said that his energy signature wasn't purely dragon with a dark thing that resemble Loki appearing before Ophis (2° point to Loki's curse as trigger)

4) Ophis replied with a "something is inside him"

5) Issei go out of the imperfect and Ophis have that black thing in her hand (3° point to Loki's curse as trigger)

if this 5 thing aren't enough than in the ep 10 Loki say that the Ouroboros "did something unnecessary" referring the extraction of his curse from Issei, then the red shard from where come out the fake Issei how was "infected" by Loki's curse? simple, the JD was triggered by the curse infecting the JD in that moment and when the shard was separated from Issei then a "portion" of the curse remained in it creating the fake Issei

Conclusion: say that in the anime the Issei's JD was triggered by Loki's curse is right 