Who was Luo Cheng in the Tang Dynasty?

Luo Cheng is the seventh hero in The Romance of Sui and Tang Dynasties, and he is also called the Tang Dynasty. In the historical novel Romance of Sui and Tang Dynasties won by Chu people in the early Qing Dynasty, Luo Cheng is the son of Luo Yi, the king of Yanshan Mountain in Beiping, and also a cousin who is proficient in marksmanship. Because of his fair skin and handsome appearance, he was called "cold-faced sniper Cheng" and then joined the rebels in Wagangzhai with Cheng. After the dissolution, Wagangjun joined Wang and switched. The novel is called Zhao Yun, an ever-victorious general who can be compared with the Three Kingdoms. Later, in the battle between Tang Jun and the Liu Heita army, he was calculated by Prince Li and Li Yuanji, the king of Qi, and was tricked into the mud river by Sue and killed by an arrow. Luocun Town, Zichuan District, Zibo City, Shandong Province, is the hometown of Luo Cheng. There was a real Luo Shixin in the Sui and Tang Dynasties, which had many similarities with Luo Cheng in the novel, so it was considered as the historical prototype of Luo Cheng.