Have no idea what High school DxD is but I am a holy man, I see angels and demons and I subscribe. 

So I would like to get number 4, be one of the angels that "fell" during the rebellion but in fact he was in a mission undercover in hell to keep track of Lucifer/Satan/Devil's doings(whoever the leader is). Being found out at last he was "redeemed" and accepted back to the gates of heaven. He is the Angel of Death.

....did a rebellion even happen in the DxD universe?