There once was a beautiful priestess who traveled for many years. Everywhere she went there were jealous women whom envied her beauty. What those women didn't know however, was that the priestess had a dark secret she was determined to hide. That secret was a beast named Tsumeato, who was sealed inside the priestess. Tsumeato absolutely hated being stuck like a caged animal and verbally abused the priestess inside her head every day.
The priestess, named Hisoka, was strong willed and never gave into Tsumeato's constant demands to be set free. Hisoka used much of her spiritual powers to keep the seal on Tsumeato strong so that she would never be free. Of course, those results came with a terrible price. On the nights of the full moon Tsumeato's seal would weaken to the point that Tsumeato could possess Hisoka and go on a killing spree.
The innocent civilians were beyond horrified when Tsumeato, possessing the beautiful priestess Hisoka, chased them down and left nothing but a blood bath behind. After those nights of terror Hisoka would always awake to a village or city with blood and corpses everywhere. Hisoka knew she had to put a stop to this madness and sought out someone powerful enough to slay Tsumeato.
She searched for months crossing mountains and vast rivers until she finally found the Sun Goddess Amaterasu. She knew what Hisoka wanted but would only help the priestess if she became a servant for the Sun Goddess. Hisoka quickly complied with the agreement and released Tsumeato's seal. Tsumeato was strong, but definitely no match against the Sun Goddess. After slaying the beast, Hisoka went with Amaterasu to her temple and lived a long happy life knowing that she would never be blamed for anyone else dead.
Moral of story: Appearances can be deceiving