Feast of Souls by C.S. Friedman

"Feast of Souls" is the first book in the "Magister Trilogy" by C.S. Friedman. On the front of the book it poses an important question, "What price would you pay for power?" and, in many ways, that's the central question of the book. In this world each person has what's known as their "soul fire." A witch is a person who has the ability to draw on their own soul fire to perform magic. The only problem is that there is a limit to the amount of soul fire each person has, and every act of magic takes away precious minutes from that person's life span.

The Magisters are set apart from the witches in that they are virtually immortal. No one outside their order knows how they've achieved this, and they keep it that way because the secret is a dark and terrible one. The Magisters have learned how to feed off of the soul fires of other people, thus protecting their own life spans, and allowing them to use magic without any personal cost.

Magisters are known for being ruthless, and they are all without exception male. No one knows why this is, it simply is. Until a young woman named Kamala challenges that which is known, and manages to become the first woman Magister. As such she faces many unique challenges, especially because she knows it's not wise to announce her existence to the rest of the Magisters before she's comfortable with her power.

Then Kamala finds herself in yet another unique and difficult position. Normally the Magisters never know who's soul it is that they feed of off, they merely know when it expires and they must fasten onto another. Kamala not only meets the man whose soul fire she is stealing, she falls in love with him.

While Kamala is going through her own drama, the land itself is facing great turmoil. Hundreds of years ago an ancient evil was banished. Imprisoned in the north where there were always those guarding to insure it never returned, but other than those special few, many no longer believed that this evil even existed. Until one day it breaks through to ravage the land.