Source: Book of Spirits p147
This Numen is a more powerful version of Soul Snatch that also functions against supernaturals who possess a soul. As with that Numen, Soul Harvest functions just as the Claim Numen except that success on the spirit’s part means it grasps the victim’s soul instead of Riding its body. The victim must succeed upon a Stamina roll or fall unconscious. Even if conscious, the victim may not spend points of Willpower, expend points of a supernatural power trait or use any supernatural ability without the consent of the Harvester spirit. The victim cannot regain Willpower if its soul has been harvested. The spirit has full knowledge of its victim’s thoughts and actions, no matter its location. If the supernatural has an Essence trait, the being may use these points of Essence as its own. It may also choose to feed upon the victim’s soul at its leisure. Each hour the spirit does so, it gains two points of Essence per dot consumed — feeding first on its prey’s Willpower then its dots of Supernatural Advantage. Each hour that the spirit is feeding, the victim must again succeed upon a Stamina roll or fall unconscious due to the pain. When the spirit is finished feeding, the creature’s soul is destroyed.