Aeon, being the Trinity goddess of time, controls far more than you may at first think of. Not only can she control the flow of time, but she can see all possible choices a person may make, thus allowing her to also see alternate realities. Using her powerful parasite, Khronos, she can actually manipulate multiple timelines and bring pieces of those into her own reality.
An image of Aeon can be seen in stained glass, but also in the lower right of the stone statue of the Grand Cathedral stage in Skullgirls. In addition, Aeon is seen in person at the end of Double's story mode speaking with her goddess sister Venus. Aeon is playing the Skullgirls videogame, and she explains to Venus that each of the story modes for the characters are all possible real timelines, and the game is an easy way for her to interact with them. She also mentions that there could be a timeline that also intersects with their own.
And that is in fact how the designers of Skullgirls, now under the banner of Lab Zero Games, proposed that Aeon could be made a DLC character. During an Indiegogo powered fund raiser to make a single DLC character, Squigly, one of the stretch goals was to make additional DLC characters based on a fan favorite vote. Aeon, along with 31 addition characters, were revealed for this vote. Not only was this goal met, but a 2nd fan voted character was also funded, with each character being selected after 4 rounds of votes to whittle down the roster. Aeon has so far made it past the first 2 rounds.