The Spirit Wrack was acquired and used by Kain during the events of Blood Omen: Legacy of Kain in the late stages of the game. It was found by him inside a cave right after leaving Avernus, just outside of Willendorf. Could be considered an upgraded version of the Control Mind spell, because it allowed Kain to fire a magical projectile that replaced any creature's Soul with his own, taking full control of his victim's body. Like the Control Mind spell, while his soul was absent, Kain's body would be fully protected by a Repel-like barrier; and if he decided to release his grip from the possessed body or it sustained enough damage, that body would inevitably perish.