She is the miko of the Hakurei Shrine, a remote building far in the east where the boundaries of Gensōkyō and the human world overlap. It is believed that she is the 13th of her line.
Reimu is very easygoing — some would say lazy — and hates to train. As such, even though she's naturally talented, her offensive and magical abilities are only average. However, she has a strong sense of duty, and if it's for the sake of Gensokyo she can overcome almost any obstacle through sheer perseverance.
Her main abilities are flying in the sky, good intuition, and getting along with everyone; even those who were once her enemies. In the games, she is characterized by her homing amulets and yin-yang orbs.