(Touhou 8, human form) Brown eyes and long silver hair with blue highlights. Wears a hat that looks like some kind of building with a red ribbon on top and glyphs inscribed along its side. Her dress is dark blue with white short sleeves, and a red ribbon is tied to the bottom of the collar.
(Touhou 8, hakutaku form) Red eyes, long silver hair with green highlights, and horns. Her left horn is decorated with a red ribbon. Her dress is dark green with white short sleeves, and a red ribbon is tied to the bottom of the collar.
(Touhou 13.5, human form) Same as above, except her hat is simpler.
During Imperishable Night, Keine Kamishirasawa, being sensitive to the moon herself, sensed the strange events that were occurring. As a safeguard, she hid the village's history, making it as if there had never been a village there to begin with, so that the inhabitants would be protected from any youkai. After being defeated, Keine pointed the heroines toward the ones responsible for the fake moon in the sky. Later, during the Extra Stage, Keine acted as guardian of Fujiwara no Mokou and attempts to stop the player from reaching and facing Mokou.
Keine seems to have a strong desire to protect humans and would probably be the safest person in Gensokyo for any human to be around.