>>717546935
But the entire reason demons were able to become involved was because the Church was corrupt to begin with.

It was due to the Glabados' plan of using the legend of the Zodiac Braves to unite the people under their banner that the Holy Stones found themselves in the hands of the very people that became Lucavi Demons. The demonic incursion was purely opportunistic; the real problems that Ivalice faced were caused by political turmoil following the recent 50 years war, and the greed and corruption of its leadership.