The Marrowfiend are subterranean monsters with fire for blood and a penchant for posthumous explosions. Never had they been seen on the surface until the Marrow Wound was torn open following the second Great Cataclysm. They were greatly enhanced by their former commander, the Herald of Woe from approx 62GE to 718GE when the Herald was defeated. During this period they ravaged the land of Atraxia, robbing it of all vitality and forcing the Atraxians to the sky islands on which they now primarily reside.

During their reign of terror under their Herald, the Marrowfiends were empowered with the gift of reincarnation. Once defeated their essence would be recaptured and grown a new body from the Marrow Wound. If that was not possible for distance or otherwise, the Marrowfiend would become undead shamblers with limited prowess until they were permanently destroyed or made it close enough to the Wound to reincarnate.

Following 713GE the Marrowfiend have become a manageable and occasional pest, retreating almost entirely underground.