Zhang Liao
When Zhang Liao was captured and brought before Cao Cao after the battle, he scorned Lü Bu for his cowardly behaviour. He showed no fear and even remarked that Cao Cao was lucky to have survived the blaze at Puyang (referring to an earlier battle in which Cao was almost killed). Cao Cao was furious and he drew his sword and wanted to kill Zhang Liao, but Guan Yu and Liu Bei stopped him and pleaded with him to spare Zhang. Guan Yu even knelt down. Cao Cao laughed, sheathed his sword, and said, "I also know Wenyuan (Zhang Liao's courtesy name) is a loyal and righteous man. I was just testing him." He then personally released Zhang Liao from his bonds, took off his coat and wrapped it around Zhang, and offered him a seat. Zhang Liao was moved by Cao Cao's sincerity so he submitted to Cao.