Meng Da
Meng Da was afraid that he would be punished for refusing to help Guan Yu. At the time, his relationship with Liu Feng was also strained, hence he brought 4,000 soldiers with him and defected to Liu Bei's rival Cao Pi, who gave him a warm welcome. Meng Da then wrote a letter to Liu Feng, informing the latter that he was in grave danger, because someone close to Liu Bei had spoken ill of him, and he urged Liu Feng to surrender to Wei as well. However, Liu Feng ignored Meng Da's advice and returned to Chengdu, where he was executed by his adoptive father for failing to reinforce Guan Yu and failing to stop Meng Da from defecting.