簡単な回答
A persona defines who the user is inside the scene, while the character card defines the AI character. Separating them makes it easier to reuse one user identity across many characters.
平易な言葉の意味
If the character card answers 'who is the AI?', the persona answers 'who am I in this story?'
Persona support improves continuity, reduces repeated setup, and helps users switch between story roles without rewriting every character card.
OnlyKin uses personas as reusable roleplay context that can support many different character chats.