Fa Hai, abbot of Jinshan Temple and a Buddhist monk, serves as the primary antagonist opposing Bai Suzhen (the White Snake spirit) and Xu Xian. Originally a terrapin training near West Lake, he witnessed Bai Suzhen consume immortality-granting tangyuan meant for Xu Xian. This imbued her with great power, fueling his jealousy and igniting their conflict. Driven by a rigid interpretation of Buddhist doctrine, Fa Hai condemns interspecies relationships, especially between humans and spirits, as violations of cosmic law. He deems Bai Suzhen's marriage to Xu Xian unnatural and dangerous, dismissing her benevolent actions and genuine love. His methods escalate: he first warns Xu Xian of Bai Suzhen's true nature, then orchestrates events during the Dragon Boat Festival by tricking her into consuming Realgar wine. This forces her serpent form reveal, causing Xu Xian's fatal shock. After Bai Suzhen revives Xu Xian with a stolen herb, Fa Hai imprisons Xu Xian at Jinshan Temple under the pretense of protection. This provokes Bai Suzhen and her companion Xiaoqing (the Green Snake) to attack the temple. Fa Hai summons protective Buddhist deities like Skanda and Sangharama. Bai Suzhen retaliates by flooding the temple, causing civilian casualties and highlighting the destructive consequences of Fa Hai's actions. Despite Xu Xian's acceptance of Bai Suzhen and pleas for mercy, Fa Hai captures her with a golden alms bowl, sealing her beneath Leifeng Pagoda. He declares her imprisonment eternal—lasting until the pagoda collapses or West Lake dries. Fa Hai's portrayal has shifted across adaptations. Early Ming-dynasty versions, like Feng Menglong's 1624 *Stories to Caution the World*, depict him as a righteous hero saving Xu Xian from a demon. Later Qing-dynasty operas and novels increasingly humanize Bai Suzhen, reframing Fa Hai as vindictive. Twentieth-century interpretations cast him as embodying religious intolerance, destroying a loving marriage under piety's guise. His fanaticism intensifies upon learning of Bai Suzhen's pregnancy, viewing the human-spirit hybrid as an abomination. In sequel narratives, Fa Hai faces repercussions. Xiaoqing, after training, returns to defeat him and destroy Jinshan Temple. In some versions, Bai Suzhen’s son, Xu Mengjiao, later liberates his mother, leading to Fa Hai’s final humiliation—he hides inside a crab shell to evade divine punishment, explaining a folk belief about crab anatomy. His magical abilities include invoking divine guardians, deploying potent artifacts like the alms bowl, and leveraging rituals such as Realgar wine to exploit spiritual weaknesses.