Ummm... first of all, I'm not a "core identity". I'm the one who's corporeal for all purposes of interacting with other people. Your question seems odd to me - it's like asking "how did you figure out/discover that you have siblings?". I don't remember either the birth of my brother-in-the-flesh or the first appearance of the 'brothers' who share my own body; in both cases, seems like they've just always been around.
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