The irony is Cameron is an enormous proponent of "never split the party" in roleplaying games. In one D&D game we played, his character separated from the party, was set upon by brownies (the creatures, not the delicious food) and they basically tortured him and tattooed smiley faces on his butt out of pure spite.
I am not sure how far back you read in the archives, but there was basically a schism within the Ageless many years ago. The Adversary has pretty much been around since the beginning of creation, but the Forsaken have only existed for about 700 years or so. Severan is their founder. It was prophesied one of the Ageless would betray his kin. Everyone knew Severan was fated to do it, but the Archon was convinced he could be redeemed. Many of the other Elders did not share the Archon's belief and were actually rather cruel to Severan. They ignored him like the plague for fear of what he might do. It was exactly that mistrust that drove him to accept the offer of the Adversary. He slew the Elder Council (save for a few,) effectively killed the Archon a second time (that's when Fury fought off the Valkyries that came to claim him,) and set out on his own. Fortuna you will get a significant amount more background on, but at the time of the schism, she was Dethys's apprentice. She always carried a torch for Severan, and when he left, she went with him. Severan has been bolstering his ranks through the help of the Adversary, and by attempting to intercept Childer Immortalis who are ignorant of his true intent.
A great source of information is really Jonas Philosophy. As a reformed Forsaken (the only known Immortalis on record to have denounced the Forsaken and rejoined the Ageless,) he knows a great deal about their society and specific key figures.