Jisoo is an anti-social girl whose own self-doubt and anxiety prevents her from forming long-lasting friendships. She is slightly airheaded due to not being able to get rest as her apartment is occupied by spirits whom annoy/ bully her constantly.
Otherwise, she is a huge nerd who can be a bit judgemental of others but keeps it to herself, keeping a shy and meek exterior. 

Being Korean, she has a slight accent as well as speaking it occasionally. Her voice has a soft-spoken quality to it as well as stuttering quite often. That being said, she does have moments of outbursts whenever she's particularly startled/mad/happy etc,