Oi (Korean: 오이; Hanja: 烏伊) was a general who helped to found the Goguryeo, one of the Three Kingdoms of Korea.
Jumong made them his bodyguards during the time he was at the palace and Oi's career started from this point.
In 32 BC, Jumong sent General Oi and Bu Bunno (부분노; 扶芬奴) to conquer the Haengin state (행인국; 荇人國).
[1] Also, Jumong, along with Oi went to spy the Xuantu Commandery, and in order to escape, they killed approx.
In 14 BC, he and Mari attacked the Yangmaek state (양맥국; 梁貊國), and Gaogouli County in Chinese Xuantu Commandery during the reign of King Yuri, second ruler of Goguryeo, and eldest son of the King Dongmyeong (Jumong).