Magister Trilogy

A trilogy of fantasy novels by C.S. Friedman. The books' titles in order are Feast of Souls, Wings of Wrath and Legacy of Kings.

The series takes place on an unnamed fantasy world, where magic is fueled by the power of human souls, or athra. Every time a witch casts a spell, it uses up a portion of his or her allotted lifespan. The exception to this rule are the titular Magisters, a brotherhood of magic users whose powers and lifespans are unlimited. They guard the secret of their power closely, fearing that the rest of the human population would turn against them if it was revealed.

The series focuses largely on Kamala, the first woman to successfully make the Transition and become a Magister. Other major characters are Andovan Aurelius, a young prince who has contracted a mysterious and uncurable disease known as the Wasting, Colivar, an ancient and powerful Magister, and Siderea Aminestas, the Witch Queen of the free state Sankara. The events are set against a backdrop of ancient enemies returning after thousands of years to threaten human civilization.

Tropes used in Magister Trilogy include:

Action Girl - Kamala and Gwynofar
Exclusively Evil: Played straight in the first book with the Souleaters. Played with in the second book, which recasts them as animalistic predators.
Ancient Tradition: The Protectors, who watch for the return of the Souleaters, mankind's ancient enemy, while maintaining the Wrath of the Gods which keeps the Souleaters at bay.
Anti-Hero - Kamala, Colivar, and any other Magister who's a protagonist. Kamala in particular is a Type IV- she's got just enough of a sense of compassion and justice to keep her sympathetic when taken together with her exceptionally crappy backstory, but her magic is still Powered by a Forsaken Child and there's a very real, very scary darkness in her.
Anti-Villain - Siderea in the second book. Less so in the third, as she's started to get Drunk on the Dark Side from being bonded to her Souleater.
Arch Enemy: Nyuku to Colivar
Badass Normal: Rhys takes down a Souleater, solo. Also Andovan, especially since he's dying from the Wasting.
Big Bad Duumvirate: Nyuku and Siderea by Legacy of Kings.
Black Cloak: Black is the official color of the Magisters (since a pure black that doesn't fade can only be produced by magic), and many of them wear cloaks in that color (though any clothing can cound as a Magister "uniform" so long as it's jet black).
Blue and Orange Morality: Though intelligent, the Souleaters are very primal and as such aren't driven by anything that particularly resembles human morality. This is lessened somewhat when they start bonding with humans. In the end, though, understanding the Blue and Orange Morality of Souleaters lets Colivar and Kamal exploit it to defeat them.
Bond Creatures: Humans can link with Souleaters in a process that grants the human immortality and the ability to share in the Souleater's powers, and gives the Souleater the enhanced self-awareness to overcome its baser instincts.
Broken Bird: Kamala, so much. She gets some better across the series.
Cast From Lifespan: An important element of the trilogy. Every spell costs someone part of their life. The Magisters only pass the expense to some unfortunate stranger.
Charm Person: All Souleaters can do this to humans, so that their prey is immobilized and loses the will to resist them. Souleater queens can affect other Souleaters as well.
The Chessmaster - ALL of the Magisters.
The Corrupter - Kostas, most evident in his effect on Danton. The High King starts out a ruthless but pragmatic conqueror, but the more time he spends around Kostas the more he starts acting like a stereotypical Evil Overlord.
Court Mage: The preferred profession of many Magisters. Kings consider a Magister advisor indispensible to their reigns. In-universe, this carries the official title of "Magister Royal".
Determinator - Any Magister has to be this by definition- if you're not determined to survive at any cost, you can't latch onto someone else's soulfire to drain.
Disc One Final Boss: Kostas.
Fate Worse Than Death - How the Spears were created
Eldritch Abomination: The Souleaters
The Empire - The High Kingdom
The End of the World as We Know It - What happens if the Souleaters win
Everyone Calls Him "Barkeep" - Species-wide example. The race that the villains belong to are formally called "ikati", but they're normally just called "Souleaters" because, well, that's what they do.
Evil Chancellor - Kostas. Some other court Magisters are like this; others serve their monarchs faithfully since it nets them a secure power base to plot against each other.
Evil-Detecting Dog - The castle dogs don't like Kostas.
Evil Sorcerer - Depending on where you place the "evil" cutoff, any and all Magisters could qualify. The humans who bond Souleaters are an even better example, most visibly Kostas and Nyuku.
Evil Versus Evil - The Magisters versus the Souleaters.
From Nobody to Nightmare: Nyuku was a barbarian kid from a village on the very edge of human civilization. Siderea was originally a pleasure slave who managed to scheme herself into a crown. They end up the two main human villains of the series.
Gambit Pileup - Just another day in the life of a Magister.
Gender Bender: Turns out that Kamala was actually not the first female Magister. Lazaroth was a woman who shapeshifted into a man and assumed a male identity after coming into her powers in order to be accepted into Magister society. She hates that Kamala is (fairly) open about being a female Magister, since that makes all of Lazaroth's efforts look pointless. There may be other genderbent women hiding out among the Magisters- it's left deliberately unclear.
Gender-Restricted Ability - Subverted. The Magisters are supposed to be all men, not from being gender-excusive but because women simply can't use that power... and then Kamala comes along... Although it turns out she wasn't the first female Magister, and her abilities are slightly different from a male Magister's because they echo the disparity between male and female Souleaters.
Green Lantern Ring - Magic can be used for virtually anything... so long as you're willing to pay the price for it (or in the case of Magisters, make someone else pay the price).
Grey and Grey Morality - Especially after Siderea bonds with the Souleater queen.
- More like Black and Grey Morality. If the Magisters win, individual consorts will be drained of life and large-scale chessmastery will occur. If the Souleaters win, human civilization collapses, potentially permanently.
I'm Having Soul Pains - The Wasting
Immortality Immorality: The only immortality to be found in this trilogy involves stealing life from others, either by draining one person dry at a time yourself, or by bonding with a Souleater, which will feed on lots of people and let you draw on the overflow.
Lady of War: Gwynofar, being a noblewoman from a Proud Warrior Race, always had the attitude; as of Legacy of Kings she develops the fighting skills to back it up.
Our Dragons Are Different: The term "Dragon" is never used for the Souleaters, but they are very clearly designed to bring that kind of being to mind.
Our Souls Are Different: the athra, or soulfire, is an energy source that everybody has; witches can tap into it in order to produce magical effects, but every spell burns up a little of it and slightly shortens the witch's life. The process of becoming a Magister involves deliberately burning your athra out so that you latch onto someone else's instead. Whenever their "consort" burns out, they then latch onto someone else, rendering them effectively immortal and capable of perfoming tremendous feats of magic.
Powered by a Forsaken Child - The Magisters and the Souleaters. There's a reason for the similarity of their abilities...
Real Women Never Wear Dresses- Kamala hates women's clothing and dresses like a man if at all possible. Justified because of her exceptionally traumatic backstory as a child prostitute- she thinks that showing femininity is the same as showing weakness, and she will not be weak. Other female characters don't have a problem with being girly.
Really Seven Hundred Years Old: Any Magister or Souleater-bonded is potentially this, since they don't die from old age and can change how old they look.
Shadow Archetype: Lazaroth for Kamala; Nyuku for Colivar.
Silk Hiding Steel: Queen Gwynofar.
Too Good for This Sinful Earth: Andovan. Poor doomed Andovan.
The Vamp: Siderea
With Great Power Comes Great Insanity: Bonding with a Souleater will cause this, as its incredibly aggressive, territorial personality starts bleeding over into you. The Magisters are a less extreme, but still visible, example because they all draw to a greater or lesser degree on Souleater power.
Worthy Opponent: All the Magisters view each other this way; they respect one another's abilities but their pride and residual Souleater instincts keep them in constant competition with each other. This is most obvious in the relationship between Ramirus and Colivar.
Xanatos Gambit - The normal modus operandi for Magisters.