Aeons are powerful creatures only a summoner can use in battle. Most aeons resemble their respective fayth, so it can be assumed the aeon takes on aspects of the person whose soul is sealed inside the fayth statue.
These little guys can only be found on Hokkaido, one of Japan’s most unspoiled islands (Source: http://ift.tt/2hqSRds)
Sphinx's Blog of Randomness 