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I see three influences on Anima. The artwork of H.R. Geiger (overall design), the
Hellraiser movies (chains and bondage), and (maybe) Ariel in
Soul Reaver (the Fayth of Anima).
Basically I see Aeons as a reflection of the inner soul of the Fayth. Since the Fayth of Anima was a tortured sad woman imprisoned by fate, her Aeon embodied these qualities.