Angel Para Bellum 1-2

After the death of Mitsuru's family, the woman who cared for him in his grief, called Kyrie, also vanished. Mitsuru's misfortune only intensified when a demonic kidnapping thrust him into a struggle between angels and demons! Apparently, he is a "Nephilim", and he is under the protection of two angels, Azrael and Gabriel (the woman he previously knew as Kyrie). What is Mitsuru's role in the coming crisis between the angels and demons?