After her Ankimon-in's Slayer eventually died in 980, the priest Bennin was assigned for the new Slayer, Kishi Minomoto. The girl was moved into the palace of the Great Lady Ankimon-in as her lady in waiting, where she was named Lady Shobu.
The Slayer eventually discovered that Bennin was secretly his brother Migoto instead, a vampire who had been sacrificing Slayers to a dragon in order to maintain his immortal life. After Kishi defeated Migoto, the Great Lady Ankimon-in arrived and Kishi told everything to her. In turn, the Great Lady revealed that she was the watcher of the past Slayer and intended to request to be Kishi's watcher as well, training her to be a lady during the day and a Slayer during the night.