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During the Sui and Tang dynasties, Shan Xiongxin was defeated by Yuchi Gong and returned to his camp, where he sought out Luo Cheng, the 'One-Character Parallel King.'
Upon hearing of the defeat, Luo Cheng led his troops out to confront the enemy. He saw Yuchi Gong with a very unpleasant black face.
Without a word, he immediately engaged him in a fierce fight. After a few rounds, Yuchi Gong was thoroughly defeated and fled.