I understood the gaining Skolas powers to him controlling the Oracles. I did not see him as a messenger so much as a step in the pattern. The messenger is Oryx, borne on black wings. Also, while reading the Queen Gambit, I realized she directly says to send a message to Osiris and Eris after Skolas sends his message. That pretty much end all confirms the Queen 2 as Eris and Osiris- which in turns confirms Mara as the "Queen"