I am using the word 'avatar' in my work in the sense that an avatar is the physical representation of some higher entity. We could say that a particular person, animal or object is the avatar of a deity, or that a symbol or picture is the avatar of a person, or that a player-character in a computer game is the avatar of the player. For example, my Stack Exchange avatar is a red 'W' on a blue and green field.
I am looking for a single word, or failing that, a short descriptor that is a generic term for the person or entity that has one or more avatars.
To use an example from mythology with the correct semantic context for my question, we have the sentence:
Rama says, 'I am an avatar of Vishnu'.
I'm looking for a word (or short phrase) to fit in the paraphrased sentence from the example above:
Rama says 'Vishnu is my _____'.
Where _____ is the relational antonym of avatar.
Edit: 'opposite' changed to 'relational antonym'.