Sankyaku (山客, mountain guests) are people who emerge from the mountains. They are people who are swept away from China and end up at the foot of the Kongou Mountains, which border the four inner seas of the Twelve Kingdoms.
Like kaikyaku, sankyaku cannot return to China by ordinary means and struggle with learning to communicate and avoiding persecution in the Twelve Kingdoms.
Rakushun claims to Youko Nakajima that sankyaku and kaikyaku bring rare things to the world of the Twelve Kingdoms, including paper, ceramics, print technology, and medicine.
One sankyaku is credited for introducing Buddhism into the Twelve Kingdoms during the reign of Hitsu-Ou (必王, the Proof-King) during the twelfth or thirteenth dynasty of Hou.
The sankyaku is credited for establishing the first Buddhist temple in Hou, and the tradition of cremating the dead, which is still followed in the kingdoms of Hou, Ren, En, and Sou.