Yu Dayong (谷大用; died 1526), also known as the Slaver, was one of the Eight Tigers, a group of powerful Templar eunuchs that controlled the Chinese imperial court during the reign of the Zhengde and Jiajing Emperors of the Ming dynasty.
After the Zhengde Emperor died in 1521, the Templars ensured that his cousin Zhu Houcong would succeed him as Emperor. They then appointed eunuchs, one of them being Yu Dayong, to control the new Emperor, allowing the Eight Tigers to rule in his stead.
Possessing an interest in trade and foreign languages, Yu Dayong would subsequently enforce the slave trade, selling opponents to the Portuguese and making huge profits while also humiliating and exiling the enemies of the Templars. He later played a role in initiating the Great Rites Controversy, causing the Chinese Brotherhood to be almost entirely eradicated.
In 1526, fellow Tiger Gao Feng gave the Precursor box, a First Civilization artifact he had stolen from the Assassin Shao Jun, to Yu Dayong. Shortly thereafter, Gao Feng was killed, leading Yu Dayong to double patrols at his fortress in Macau. He was nevertheless assassinated there by Shao Jun, who took back the Precursor box from him.
- While he bears the name "Yu Dayong" in Assassin's Creed Chronicles: China, the name of his real-life, historical counterpart is "Gu Dayong" (谷大用). His name in the game may be an incorrect transliteration of 谷大用 or it may be an intentional name-change, as Yu Dayong is pronounced correctly as such by the Mandarin-speaking guards.
- The surname Gǔ (谷) means "valley" while the personal name Dàyòng (大用) literally translates to "great use". Dàyòng(大用) is an archaic term which, besides the straightforward meaning of "very useful", can also mean "to empower [somebody by putting that person in a powerful position]".
- In the English version of Assassin's Creed: Blade of Shao Jun, he is named "Gu Dayong".