Sairin is the current kirin of Sai.
Before selecting Kouko as the monarch of Sai, Sairin had chosen a king known as Shishou, who climbed Mount Hou after the death of the king who preceded him. At the beginning of his reign, he presented Sairin with the royal treasure of Sai, a jewelled branch called the kashokada, as a promise to rule his country well and bring about prosperity. However, during his twenty year reign, his actions caused Sairin to contract shitsudou. Realizing he had lost the way, Shishou ascended Mount Hou to abdicate the throne and took his life. Sairin chose Kouko as the next king and continues to always carry a branch with leaves on it, as a memento of the broken promise Shishou had made to her that he would govern his country well.
(Source: wikia)