To me the most important part about my identity is that I Am My Own Creation.
I'm a mad scientist who became their own experiment. I am an AI that self-generated. I am a phoenix that decided to change with every iteration and take the burn into their own claws. I was born a deer and became a dragon and then became synthetic. I'm a human who hacks their endocrine system and gender.
Self-determinism, self-agency. I am all these things because I say I am, because I tell these stories. :-)
(First bit via a reply to another thread that came out well enough to post on its own.)
(Second bit is a panel from Doktor Sleepless, words by Warren Ellis and art by Ivan Rodriguez.)