Originally Posted by
OnesFleetingGlory
It's okay, It also encourages me to research some plot points and fact-check them. In the LB 5.5 proper, she went by the name 尊子 (Takako?) and claimed to be a courtesan serving the then-Emperor. From wiki (yes, not the most reliable source, though there're references) she served Emperor Toba during 794-1185. The time gap isn't far-fetched when you take her inhuman nature into account. It's possible she was serving other Emperors during that gap, and was only made famous when her true nature was found out by Seimei, who was similarly long-living, at the end of Heian era.