Cheng Lingsu (simplified: 程灵素, traditional: 程靈素, pinyin: Chéng Língsù, jyutping: cing4 ling4 sou3) was the last disciple of Great Master Wuchen (无嗔大师), the true King of Venoms, and the heir to his book, the Divine Treatise of the Medicine King (药王神篇). A slight, sallow girl living alone by Dongting Lake, she cured Miao Renfeng’s poisoned eyes, became Hu Fei’s sworn sister, and broke up Fuk’anggan’s Grand Assembly of Zhangmen under Heaven. She died at eighteen, sucking poison from Hu Fei’s hand, and her last trap killed the two disciples who had betrayed her shifu (SIDE ch. 9–12, 19, 20).
Biography
By Dongting Lake
Cheng Lingsu’s parents were dead, and she lived alone in a cottage with a flower garden near the town of White Horse Temple (白马寺) by Dongting Lake. Her name comes from the two medical classics Lingshu (灵枢) and Suwen (素问). She looked sixteen or seventeen but had the build of a girl of fourteen: thin shoulders, a hungry, sallow face and thin, dry, yellowish hair, with only her eyes, very large and bright, out of the ordinary (SIDE ch. 9).
Wuchen had taken three disciples, Murong Jingyue, Jiang Tieshan and Xue Que. Seeing how they fought among themselves and how freely they used their poisons, and fearing that no one could restrain them after his death, he took her on late in life as his fourth and last disciple (SIDE ch. 10).
Hu Fei
Hu Fei and Zhong Zhaowen came looking for the King of Venoms, because the Broken Gut Grass (断肠草) that had blinded Miao Renfeng was said to be his. Cheng Lingsu, weeding her garden, would not give them directions, but set Hu Fei to watering her blue flowers with diluted manure. He did the job with care, and she gave him two of the flowers and sent the pair the long way round, so that they reached the Medicine King Manor after dark, when the flowers could protect them from the poison of the blood dwarf chestnuts around it (SIDE ch. 9, 10). That night she fed Hu Fei, drugged the wary Zhong Zhaowen with a flower whose scent made him drunk, and told Hu Fei her name (SIDE ch. 9).
She then showed Hu Fei her shifu’s death. With a forged letter she drew Jiang Tieshan and Xue Que to a wood at midnight, where Hu Fei unknowingly set down Murong Jingyue, whom she had overpowered and packed in a basket. When the three fell to fighting, their shifu’s last message to them glowed on the letter in the dark, telling them to stop harming one another. She then showed them his last note to her: if any of them grieved for him, she was to show them his book; if none did, they were his disciples no longer. None had asked how he died; all three demanded the book and attacked her. The candle she carried, made with Seven-Heart Begonia, had already overcome Murong (SIDE ch. 9, 10).
She had poisoned Jiang Tieshan’s son with a nail tipped with Seven-Heart Begonia to draw them out. That night she had a blacksmith named Wang seal the iron manor, smoked its occupants unconscious, and cured the son. She let the blacksmith beat Jiang Tieshan for the land Jiang had taken from him, which also let out the poison in Jiang’s blood, and she left Jiang three bundles of herbs refined with Seven-Heart Begonia to hold off their enemies, the Meng family, and the unconscious Murong to cure and make peace with (SIDE ch. 10). She agreed to treat Miao Renfeng on condition that Hu Fei grant her one wish, to be named later (SIDE ch. 10).
Miao Renfeng
Cheng Lingsu drained the poison from Miao Renfeng’s eyes with a hollow gold needle and bound Seven-Heart Begonia leaves over them. Miao, taking her for the disciple of a monk he had once fought, tried to send her away rather than accept a favour under false pretences; she answered that her shifu had long since given up all anger (SIDE ch. 11). She had succeeded where her senior fellow disciples had failed for more than ten years in growing the Seven-Heart Begonia: the plant, she told Hu Fei, must be watered with wine and dies if given water (SIDE ch. 11). Her shifu’s own shifu had once obtained its seeds from overseas and could never make them grow (SIDE ch. 20).
Sworn siblings
On the road north Hu Fei asked her to become his sworn sister, since neither had any family left. Her face went white, but she knelt with him at once (SIDE ch. 12). She stood by him through the siege of the stone hut where he defended Ma Chunhua, refusing to escape without him (SIDE ch. 12). In Beijing she saved Ma Chunhua from Crane Crown Red and nux vomica with gold needles in thirteen acupoints, and disguised Hu Fei with a false beard as “Cheng Linghu”, zhangmen of the Western Marchmount Huaquan School (SIDE ch. 15). When he meant to go back into Fuk’anggan’s residence for Ma Chunhua’s sons, she threatened to go home to Hunan if he did (SIDE ch. 16).
The Grand Assembly
At the Grand Assembly she went disguised as a stooped, wrinkled, grey-haired woman puffing on a short pipe (SIDE ch. 17). She mocked the hidden-weapon expert Ke Zirong by throwing firecrackers, two of which scattered Red Scorpion Powder over the Jade Dragon Cups, so that the seven winners, among them Shi Wanchen, who called himself the King of Venoms, burnt their hands and dropped the cups (SIDE ch. 18, 19). Then she blew poisoned smoke through the hall until everyone had stomach pains and cried out that the King of Venoms was spreading poison. The guests, believing that Fuk’anggan meant to poison them, fought their way out, and the assembly broke up (SIDE ch. 19). Lu Feiqing later told the Red Flower Society’s leaders that this slight girl had wrecked an assembly Fuk’anggan had spent a year preparing (SIDE ch. 19).
Death
At a Medicine King temple outside Beijing, Shi Wanchen, Murong Jingyue and Xue Que, who had gone over to Shi, lay in wait for her. She saw through their ambush, and holding her shifu’s book she tricked Shi into testing Jade Silkworm Poison Gu, Crane Crown Red and Peacock Gall together on Murong’s palm, a mixture the book called incurable; Xue Que had to cut off his arm. When Xue Que seized her, Hu Fei broke her grip, and Shi flicked the three poisons onto the back of Hu Fei’s hand (SIDE ch. 20).
Cheng Lingsu gave Hu Fei a drug that left him unable to move or speak, pricked the vein on his hand and sucked out the poisoned blood more than forty times until it ran red. Knowing that her shifu had called the mixture incurable only because no physician would give their own life for a patient, she dressed his hand, told him that the Broken Gut Grass and the poison that killed his father had probably come from Shi Wanchen, and died beside him (SIDE ch. 20). Before dying she replaced the candle on the altar and set beside it a half-burnt one mixed with Seven-Heart Begonia. When Shi returned that night he lit the half-burnt candle as the safer one: Murong Jingyue and Xue Que died with smiles on their faces, and Shi, blinded, fled. She had used a thin candle with less poison so that Shi would live and Hu Fei would have a reason not to follow her in death (SIDE ch. 20). In her life she had never killed anyone (SIDE ch. 20).
Hu Fei cremated her and buried her ashes by his parents’ grave near Cangzhou (SIDE ch. 20).
Personality
Cheng Lingsu was clever and far-sighted, anticipating others’ moves; Hu Fei found her ten times cleverer than himself (SIDE ch. 10, 11). She was sharp-tongued and quick to take offence when he ignored her advice, but spoke tenderly when he did not (SIDE ch. 10, 16). She kept to her shifu’s rules: never to use poison that has no antidote, and to leave even great villains a way back (SIDE ch. 10, 20). She loved Hu Fei, who loved Yuan Ziyi, and never said so; her feelings are shown through the blacksmith Wang’s love song and Hu Fei’s hindsight (SIDE ch. 10, 20).
Relationships
- King of Venoms (Shifu): Great Master Wuchen, who left her his book (SIDE ch. 9, 10).
- Hu Fei (Sworn brother): She loved him and died to save him (SIDE ch. 12, 20).
- Murong Jingyue, Jiang Tieshan and Xue Que (Senior fellow disciples): She cured Jiang’s son; Murong and Xue Que betrayed their shifu and died by her last trap (SIDE ch. 10, 20).
- Shi Wanchen: Her shifu’s shidi and enemy, whom she refused to recognise as her shishu (SIDE ch. 20).
- Miao Renfeng: She cured his eyes (SIDE ch. 11).
- Yuan Ziyi: Hu Fei’s love; the two women came to respect each other (SIDE ch. 14, 20).
- Ma Chunhua: She saved her from poisoning (SIDE ch. 15).
Skills
Cheng Lingsu was a physician and poisoner of great skill: she used needle and knife to drain poison and treat wounds, grew new plants such as the blue flower that counters the blood dwarf chestnut, and built her poisons into candles, clothing, firecrackers and pipe smoke (SIDE ch. 9–11, 15, 19). Her fighting skill was modest, though her throw of a silver hairpin impressed Hu Fei (SIDE ch. 9). She was also expert at disguise (SIDE ch. 12, 15, 17).
Behind the scenes
In the afterword to Side Story of the Flying Fox, Jin Yong writes that only Cheng Lingsu’s poisoning is exaggerated in a largely realistic novel. He calls her a lovable, admirable girl, not especially pretty, whom he likes very much, and says that he wept each time he wrote about her. He also urges adapters not to add scenes of Hu Fei and Cheng Lingsu travelling a thousand li together in tender silence (SIDE afterword). In his afterword to Flying Fox of the Snowy Mountain he notes that Hu Fei, meeting Miao Ruolan, ought logically to think of Yuan Ziyi and Cheng Lingsu, but that neither character existed when that novel was written (FLY afterword).

