Lana opening a dimentional gate on Rebound p. 127

are semi-retired warrior angels, tasked with controlling the gates that angels use to access hell and the various mortal worlds. Their halos, which are solid gold discs, give them the power to open and close these gates at will. Seraphim are further distinguished by a smaller, secondary pair of wings sprouting between their main wings. Only angels who have served with great distinction, usually former generals, are granted the rank of Seraph.