全真道北五祖之一，五代时道士。名操，字昭远，又字宗成，以号行。燕山（今北京市西南宛平）人。为辽进士，又说名哲，字元（铉或玄）英。事燕主刘守光为丞相。好黄老之学。一日，有道人自称正阳子来谒，海蟾待以宾礼。道人为演清静无为之宗，金液还丹之要，并索鸡卵十枚，金钱十文，一文置几上，累十卵于金钱上，若浮图状。海蟾惊曰：“危哉！”道人曰：“居荣禄，履忧患，其危殆甚！”尽以其钱劈破掷之，辞去。海蟾大悟，遂弃官隐于华山、终南山。后得道仙去。元世祖封其为“海蟾明悟弘道真君”。元武宗加封为“海蟾明悟弘道纯佑帝君”。

(Also known as: Liu Cao (刘操), Hai Chan (海蟾), Zhao Yuan (昭远))
Liu Cao (刘操) was a Taoist of Wu Guo Period (五国) (907 AD – 960 AD) from Yan Shan (燕山). He was a talented scholar, interested in the study of Huang Lao (黄老); and worked as the Prime Minister for Liu Shou Guang (刘守光), a local king in Yan (燕). One day, a taoist self-addressed as Zheng Yang Zi (正阳子) came for a visit and asked for ten eggs and ten coins. He put an egg on top of a coin in alternate layers until they formed a shape like a tower. Master Liu was astonished and thought that the eggs in danger. The Taoist replied that as Liu was living in big fortunes and vanity, he was in fact in a more dangerous position. The Taoist then picked the eggs, dropped the coins onto the floor and left. All of a sudden, Liu Cao was awakened to see what a situation he was in, he immediately resigned from politics and lived in seclusion in Hua Mountain (华山) and Zhong Nan Mountain (终南山). Thereafter, he followed Master Zhong Li Quan and Master Lu Zu; and became one of the Northern Five Masters. Emperor Yuan Shi Zu bestowed him a title as “Hai Chan Ming Wu Hong Dao Zhen Jun” (海蟾明悟弘道真君) and Emperor Yuan Wu Zong further honoured him as “Hai Chan Ming Wu Hong Dao Chun You Di Jun” (海蟾明悟弘道纯佑帝君).