The legend of Pu Sae and Ya Sae appears in ancient documents such as the
Tamnan Phuen Mueang Chiang Mai (The Chiang Mai Chronicle), the
Tamnan Chiang Mai Pang Doem (Original Chiang Mai Chronicle), and the
Dharma Tamnan of Wat Nantharam, as well as in contemporary documents like the
Legend of Phra That Doi Kham. In addition, it also exists as a folk oral tradition, which often contains more elaborate and fantastical content. All versions of the legend emphasise the importance of Pu Sae and Ya Sae in their role as the "Kao Phi" (เก๊าผี), or the "progenitors of the spirits", for all of Chiang Mai. This is because they had as many as 32 children. Their children include figures such as Chao Luang Kham Daeng, who is the greatest of all spirits in Lanna; Chao Soi, who protects the city of
Mae Chaem; Chao Buarapha, who protects the city of
Haeng; and Chao Somphamitr, who protects the Mae Khanin forest (present-day
Hang Dong District), etc. Pu Sae and Ya Sae, however, found it impossible to abandon their primal nature entirely. They pleaded with the Buddha, asking for permission to eat human flesh at least once a year. The Buddha did not grant this request. The ogres then attempted to negotiate, gradually asking instead for animal flesh. The Buddha eventually told them to consult the local ruler regarding the matter and then departed, leaving behind a relic of his hair, which would later become enshrined at
Wat Phra That Doi Kham. They received permission from the city ruler to eat buffalo once a year. This led to the establishment of a ritual involving the sacrifice of a young buffalo—specifically one with horns no longer than its ears—known as khwai khao kham (ควายเขาคำ). The meat of this buffalo is offered as a sacrifice to the spirits of Pu Sae and Ya Sae annually on the 14th waxing moon day of the ninth month in the Northern Thai lunar calendar. In exchange for this annual offering, the two giants swore an oath to protect the city of Chiang Mai, its people, and the Buddhist faith for 5,000 years. After their deaths, they became powerful guardian spirits, or arak, whose influence over the well-being of the region necessitates the fulfilment of this ancient pact through an annual sacrificial feast. ==Liang Dong ceremony==