The angels suddenly did a pre-emptive attack on the devil side due to their confidence of reviving. The angels like the devils can actually revive as long as their soul could reach the Silver City. Adrian already confirmed this as a special trait of the angels since the game must be compensating for their small numbers.
This is also one of the reasons why the angels are wary of Adrian or anyone that is from the Church of Life and Death. Adrian made sure to destroy the souls of the angel's way towards the Silver City. He personally delivered them to the afterlife ever since he found out about this detail.
"Each and every one is clear with our assignments. Please coordinate with the one that will lead you in the fight. Also, I wish everyone to stay vigilant as angels are beings of light. That is all! Dismissed." Adrian stated as all of his guild members came out of the guild house.
