The brazier that stands atop the stairs in the great hall of our temple has always been something of a mystery to us. This is the brazier that created the beings we call the ash wraiths. This is where Andraste's followers immolated themselves and became the eternal guardians of Her temple.
I have painstakingly pieced together information from old books and from the tales and half-truths passed down to us by our forefathers. I believe I now understand the ritual used to create the wraiths. The brazier was lit with a consecrated taper, its flame taken from the everlasting fire that long ago consumed Andraste Herself. The chosen disciple would fast and pray for weeks, taking into his body nothing but a sip of water a day. When the disciple was finally ready, he would place in his mouth a flawless black pearl, and step into the flames. In ancient Tevinter, black pearls were thought to be magical, able to stop the soul from passing through the Veil when held in the mouth at the moment of death.
Thus, Andraste's disciples consigned themselves to the eternal flame; they became dust and ashes, and rose again and again to protect the most Beloved of the Maker.
-- From the journal of Father Kolgrim.