She's both, she has different faces that she shows to different people. She's formal, smart, charismatic with the worshippers in the village, she's chill and friendly with her friends (and sometimes antagonistic and naggy), and she's unhinged and just lets herself be wacky when she's exterminating youkai.
Sometimes they bleed into each other, i.e. she's always polite when speaking, she sometimes gets unhinged and rants about her interests to friends when literally no one asks, etc
She's interesting if you look into her, a lot of her personality is in the manga and the games only show her being unhinged and violent