Xy.ō was the second Imperial House (Yii'uaTao") in the Xi'an Empire (SaoXy'an). Selected by other major Houses in II.0 (878 BCE), the new Emperor Y.ah'a se Xy.ō and the rest of her House commemorated the terraforming of R.aip'uāng (Kai'pua II) to be a spiritual center of Li'tova in honor of the Ru'a Line's millennia of service.
The final Emperor Xy.ō and her entire family were exterminated by the Kr'thak in II.1706 (SEY 1305), during the Spirit Wars. Their destruction led to the Dark, a period of Xi'an history beset by anarchy and cultural decline.