Sairin is the current kirin of Sai.
Before selecting Kouko as the monarch of Sai, Sairin had chosen a king known as Shishou. After the death of his predecessor, Shishou climbed Mount Hou. At the start of his reign, he presented Sairin with Sai's royal treasure, a jewelled branch called the kashokada, symbolizing his commitment to ruling well and bringing prosperity. However, during his twenty-year rule, his actions caused Sairin to contract shitsudou. Realizing he had strayed from the right path, Shishou ascended Mount Hou to abdicate and took his own life. Sairin then chose Kouko as the next king and always carries a leafy branch as a reminder of Shishou's unfulfilled promise to govern wisely.
