Within Astral Space, everything is personified - even the Arcana. Before the Ocean Oroboros that marks the end of the Dreamtime and the beginning of the Abyss, there are found the Aeonic Citadels which house beings that embody the Arcana, some of the last remnants of the Supernal within the reaches of the Fallen World. Some claim that the Atlanteans venerated the Aeons as archangels of magic, but when they built the Celestial Ladder, they bypassed them and when they climbed up again, they found a new Citadel there and the twisting shore of unreality separating them from the Supernal. If the Aeons are a family, it is one filled with sibling rivalries. This might be founded in a common resentment of exile, or reflects a struggle with cosmic implications. They never enter one another's Citadels, so an Aeon might ask mages to spy on her “brother,” filch some item from his Citadel or embark on a strange mission that weakens a Watchtower’s influence.
Each pair of Aeons rule together in a realm that emulates one of the Watchtowers, except for Dahhak, who embodies both Arcana of his realm and the Old Man, who embodies the Abyss. Such a pair is known as a Syzygy. The names of the Aeons are known in High Speech but are too complicated for modern mages to speak. Some claim that the Aeons are mortals that were awarded with their current positions for the lives they lived and how they reflected their Arcana by some of the Ascended mages, others claim that the Aeons were once mages who chose to delay final Ascension to further the Supernal.
As personalities, Aeons seem to embody some of the more negative traits of their respective Arcana. Dahhak, for instance, is almost the embodiment of the worst traits of Mastigos in general, being an arrogant and manipulative bully who enjoys forcing repeated supplicants into worse and worse deals, while Medraut manipulates humans into tragic fates that uphold the status quo (indeed, some changelings know him by the name of Mordred, and recognize him for his Vow of All-Consuming Fire that guarantees one patroned by him will be a great leader and hero, but whose story will end bitterly for all involved). The one exception is (fittingly) the Old Man who represents the Abyss, who seems incredibly ambivalent about his role and warns people away from the path of Scelesti (but seems bound to make a deal with any who wish his tutelage in Antinomian Magic, though he drives a very hard bargain).