User blog comment:B214/Question and Answers 6/@comment-36.72.199.46-20161213181208/@comment-9595671-20161214145551

You sure? I could have sworn that Ddraig once mentioned to Issei that during the war, other creatures and humans were forced to choose sides to assure their survival with the dragons being the only exception, didn't he? That doesn't sound like only they were involved.

I mean the Christian faction was probably the major focus of it, but it's said the war enveloped the entire world too, and I doubt the other factions weren't caught in the crossfire. Ironically though, that might explain why some of the other factions aren't as into the idea of peace.