context: There were many religions practiced during the Yuan dynasty, such as Buddhism, Islam, and Christianity. The establishment of the Yuan dynasty had dramatically increased the number of Muslims in China. However, unlike the western khanates, the Yuan dynasty never converted to Islam. Instead, Kublai Khan, the founder of the Yuan dynasty, favored Buddhism, especially the Tibetan variants. As a result, Tibetan Buddhism was established as the de facto state religion. The top-level department and government agency known as the Bureau of Buddhist and Tibetan Affairs (Xuanzheng Yuan) was set up in Khanbaliq (modern Beijing) to supervise Buddhist monks throughout the empire. Since Kublai Khan only esteemed the Sakya sect of Tibetan Buddhism, other religions became less important. He and his successors kept a Sakya Imperial Preceptor (Dishi) at court. Before the end of the Yuan dynasty, 14 leaders of the Sakya sect had held the post of Imperial Preceptor, thereby enjoying special power. Furthermore, Mongol patronage of Buddhism resulted in a number of monuments of Buddhist art. Mongolian Buddhist translations, almost all from Tibetan originals, began on a large scale after 1300. Many Mongols of the upper class such as the Jalayir and the Oronar nobles as well as the emperors also patronized Confucian scholars and institutions. A considerable number of Confucian and Chinese historical works were translated into the Mongolian language.
question:  What was Kublai's least favorite sect of Tibetan Buddhism?