Su Dingfang
In the real historical records, Luo Yi really had a son called Luo Cheng. However, other than his name, no more things Luo Cheng did were recorded. The novel Shuo Tang also glorified Luo Yi. In the novel, Luo Yi showed his loyalty. However, in reality, Luo Yi switched his position between Sui and Tang Dynasties and among many warlords for several times. Also, to glorify Luo Yi and Luo Cheng, this novel defamed Su Dingfang (苏定方), who was a loyal military genius in the history but a traitor in the novel.