San's parents threw her to Moro as a sacrifice to save their own lives. When San was a baby, the wolf goddess Moro attacked her parents, who were found damaging the forest. However, she still decides to live separated from humans since she's not yet ready to forgive Eboshi and some of the others for their previous actions against the forest and its inhabitants. Despite this, she eventually falls in love with Ashitaka, and by the end of the movie, like the others, she is convinced to cease open hostilities against the resident of Irontown.

She also rejects her own humanity and seems to be quite misanthropic, thinking of herself only as a wolf. She is stubborn and protective, her primary concern being to protect the forest and animals she lives with. San is a young woman raised by the wolves and feels hatred for humans, but eventually comes to care for Ashitaka. She later wears Kaya's Crystal Dagger after Ashitaka gives it to her as thanks for saving him. The mask is red with ears and red wavy lines and three yellow holes for a mouth and eyes. She wears a mask which is her iconic feature. She is also very agile, fast, fairly strong, and appears to be really good at using daggers and spears. San is a beautiful young woman of average build (around 16–17 years old) who wears ragged clothing and a cape made of wolf's fur and has what appears to be red war paint on her face.