I don't know... I feel that if we added angels to this story, it would make it kind of predictable. Because, there are plenty of manga/manhwa stories that feature angels and demons. Most of them portray the angels not in a good light, while the demons have some goodness in there. (I'm just a bit tired of reading stories that have some "bad - corrupt" angels. ^__^) Thankfully, the few that don't follow this route, at least, maintain that there are some good non-humans/demons within the demon realm.
I'm more content with the theme of corrupt humans and evil demons verse everyone else, who are good. However, if there were angels, like in Soul Cartel (which does the whole angel/demon thing properly), then...,it's inevitable. God may have some sort of existence in this story, but this story isn't based on the Christian God. So, having angels here doesn't really make sense to me.
Ah, anyways.. . Back to this mysterious winged creature...
Read more: http://blackhaze.freeforums.net/thread/61/demon-kings-cause-death#ixzz4TV18ibM9