Li GUI

Li Gui (李軌) (died 619), courtesy name Chuze (處則), was the emperor of a short-lived state of Liang, which he established at the end of the Chinese Sui Dynasty. He governed the parts of modern Gansu west of the Yellow River. In 618, he briefly considered submitting to Emperor Gaozu of Tang (Li Yuan), with whom they both believed he had a distant family relationship, but ultimately rejected the idea. In 619, the Tang Dynasty official An Xinggui (安興貴) pretended to submit to him, and then started an uprising at his capital Wuwei (武威, in modern Wuwei, Gansu), overthrowing him and turning him over to Emperor Gaozu, who executed him.

Read more about Li Gui:  As Prince, As Emperor, Defeat and Death