Having watched this without watching the parent story i have to say i was completly lost. Random flashbacks or dreams or something keep popping up that have nothing to do with the story. Theres so many characters and i got confused who was who half the time . Theres was pretty much no plot and it was basically just pretty boys hanging out with their mates or crushs or whatever with a few bad angels kicked out of heaven or something which i didnt really follow either. So i guess i reccomend that if you really want to watch this ova watch the parent animefirst so you can actually follow the story line.