I like your writing style. I think you’ve done a good job of capturing how a crafty eldritch creature would behave should they ever be in this situation.
If I’m understanding this right, the MC chooses their name at 8 years old. What exactly were they called before that point? I understand some characters would want to change their given names, but perhaps that would have more impact if they actually had a given name before hand.
Edit: I should clarify. What I meant was “what exactly do the humans surrounding the MC call them before they change their name?”