@Kazuel: Possibily it refers to the character named here like Soror. Meanwhile the others ABYSS characters are named by their song, only the girl of "Ark" is named "Soror" in hers.
Sadi (from Seisen no Iberia)From top to bottom:
Saranda, Trin, Enja (From Seisen no Iberia)The boy from {Shounen wa tsurugi wo...}Aleksey Romanovich Zvolinskiy, and his wife, Ilene/Helene (from Moira)Sacrifice's sister (no-name character)Sophia (from Moira)Thanatos-ko.Hortense (from Roman)Hiver Laurant (from Roman)Violette (from Roman)Layla (after taken by Shaytan/from Seisen no Iberia)Shaytan (from Seisen no Iberia)Stardust (from Elysion)Yield (from Elysion)Baroque (from Elysion)El (from Elysion)Soror (from Elysion)Abyss (from Elysion)Thanatos (from Moira)Eleuseus (from Moira)LafrenzeArtemisia (from Moira)Mu & Phi (from Moira)SavantThe old Layla (before she is taken by Shaytan).Sacrifice (from Elysion)lost-ko (from lost)eien no shounen (from lost)RukiaChronicaLeontius