What are Quincy?

The Quincy are a line of spiritually aware human warriors. Originally a mixture of survivors of Hollow attacks and those who had lost loved ones to Hollows, the Quincy developed a variety of supernatural powers to hunt and kill Hollows before they attacked humans (and to destroy those who already had), including the ability to control Spiritual Energy. The Quincy are unique as far as races go in Bleach, because unlike the Hollow or Shinigami, Quincy are still technically human and reside in the world of the living. The Quincy are nearly extinct due to extermination by the Shinigami about 200 years before the main Bleach storyline.