From Introduction:
The Firehearts, defenders of the Church of the Aquiline Cross, have myth that tells of four primal elemental spirits – the Worldshaper Worm, the Tidereaver Kraken, the Sunrider Dragon, and the Stormchaser Eagle – the conflicts of which shaped the world.
At the climax of the mythic cycle, the Sunrider Dragon tricks the Stormchaser Eagle below the depths of the world, into the realm of the Worldshaper Worm, and there the dragon slays the eagle by biting out its throat. Before it can devour the eagle, however, it is forced to flee, and he has only enough time to tear the eagle’s heart from its breast and set fire to the eagle’s corpse. However, as the dragon’s flames consume the flesh of the Stormchaser Eagle, the hope remains that one day it could be reborn as a phoenix, over whom fire and death hold no sway.
Firehearts wield powers of both dragon and eagle, possessing wisdom enough to know that destruction can be as powerful a tool as healing, for in rebirth are the wounded purified. Some Firehearts seek to destroy ravages upon the innocent, and others to slay the weak and corrupted to usher them into their next life, while some devote their lives to seeking the Aquiline Heart, which will grant immortality to any who tastes of its flesh.