Frisk is a 'Fallen Savior', as some of the UMH residents call her. She was the first human to come into Mt. Ebott and truly accept the UMH residents for who they were, despite their illnesses.
Frisk's appearance isn't like her Undertale counterpart's. Instead of a striped sweater she now wears a blue short-sleeved shirt.
In a Pacifist story, Frisk is gentle and caring. She listens to everyone and helps each human/monster she comes across as much as she possibly can.