In the TV series Nirvana in Fire, Liu Fei, whose martial arts are superior, is really mentally retarded. It is mentioned in the novel that Liu Fei was plundered to Japan by pirates, and later he was drunk by some bad guys in order to control Japan for his own use. Liu Fei practiced martial arts for this, but his intelligence was impaired. Later, because the organization was destroyed, Liu Fei lived alone in the streets, and will return after being discovered by Mei. Since then, he has been following May Su Chang.

In the 26th episode, Yan Hou said that Xia Jiang's son had died long ago, but some netizens linked Liu Fei's story with it. Netizens said that Liu Fei was a child of Xiajiang, and he was a child with mental problems after he was born that year. After giving birth to Liu Fei, his mother died, and Mei Su Chang met him by chance and took him in. May Su Chang made Liu Fei learn martial arts all over the world and become a world-class master.