Tao'nuasao Y.ah'a se Xy.ō (MXY I.14539 - MXY II.262 | 1058 BCE - 542 BCE) was the first Emperor of the Second Imperial Age. During her time on the throne, she championed scientific endeavors that led to an expansion in knowledge of food preservation techniques, and increased the influence of Houses involved in the field of biology. She also partnered with the last Ru'a Emperor Se'ang to lead the terraformation of R.aip'uāng (Kai'pua II) in honor of the Ru'a family's many millennia of service.

A food microbiologist before the became Emperor, she joined her House's Council of Three when she discovered a type of bacteria that enabled quick fermentation of grains and legumes, thus staving off a potential famine on Ka'ua (Hyoton IV). When Xy.ō was selected to succeed Ru'a as the next Imperial House, she was chosen to be Emperor due to her auspicious position as the youngest of three daughters.