Okay then I don't know what drops SOV in Red EP1 Ult but we got the banner during HOD1 in the big room in ruins 2. It could be one of many enemies, hard to tell in the clusterfuck going on.
Ultimate - EP1 - Redria - Something in HOD1 Big Ruins 2 Room - Slicer of Vengeance (was in big room in ruins 2, HOD1, near end with bringers and delsabers)