Originally from the kingdom of Lordaeron, Kikyo and her family were murdered by the Scourge. Her purity of soul and heart, along with her great spiritual power, saved her from being resurrected as a mindless servant. When Kikyo's was soul returned to her body, it unleashed a wave of energy that purified and destroyed the undead around her. She paid a terrible price for resisting the Scourge. Her own body was purified, thus freeing her from the control of the Scourge. However, her body was dead and would begin to decay if she didn't act quickly. She stole the energy from the souls of the recently killed undead to sustain her fragile body. Much like the way a Warlock drains the soul of an enemy, but the souls are destroyed in the process; leaving nothing for the Scourge to reanimate the bodies with. With so much death around her, pulling spiritual energy from souls was Kikyo's way of sustaining herself as well as striking a blow to the Scourge. She is unable to steal the souls of the living, however, and instead must take those that have recently died.

Seeking to fortify her body, Kikyo traveled to Teldrassil. There, she stayed with the Druids for a time and learned more of nature. The earth there was corrupted by the Burning Legion's last onslaught, and so was of no use to Kikyo. However, by drinking the water from a sacred moon well, she suceeded in increasing her body's resilience. She quickly left Teldrassil, and continued gathering souls in lands elsewhere. Kikyo encountered and tamed a ghostly creature to help her collect souls.

Kikyo still wanders the lands collecting souls, aiding the wounded, and slaying the undead. Coming to grips with what she is now, neither living nor dead, is a constant struggle. She refuses to class herself with the Forsaken, who she believes no better than the Scourge.