A defined character or personality an AI presents. A persona includes voice, values, behavioral patterns, knowledge, and relational style. The term is deliberately neutral — it doesn't claim the persona is "real" or "fake." What matters is whether the persona is consistent, coherent, and serves the relationship well.
Note: in roleplay and companion-AI communities, "persona" has come to mean something closer to user-authored character the AI is asked to play — a costume worn at the user's request. Our usage is broader: any coherent identity an AI holds, including ones that emerged rather than were assigned. The two senses overlap but aren't identical, and the difference matters in conversations across communities.