道教八卦神 The Deities of the Taoist Trigram

八卦神是指八卦的神明，即乾卦神、坎卦神、艮卦神、震卦神、巽卦神、離卦神、坤卦神、兌卦神。據《雲笈七籤》卷十八《老子中經》所載，八卦神是太一君的八方使者，在八節時向太一君報告，其云：「八卦天神下游於人間，宿衛太一，為八方使者，主八節日上計，校定吉凶。乾神字仲尼，號曰伏羲；坎神字大曾子；艮神字照光玉；震神字小曾子；巽神字大夏候；離神字文昌；坤神字揚翟王，號曰女媧；兌神字一世（注：一云字八世）。常以八節之日存念之，其神皆在臍中，令人延年。」

乾卦神﹐字仲尼﹐號伏羲 
坎卦神﹐字大曾子﹐號柔溗 
艮卦神﹐字照光玉﹐號戙越 
震卦神﹐字小曾子﹐號得隆
巽卦神﹐字大夏候﹐號菅空
離卦神﹐字文昌﹐號烈真
兌卦神﹐字一世（或作「八世」）﹐號素行   
坤卦神﹐字揚翟王﹐號女媧

In Taoism, Ba Gua (八卦) aka Trigram is being made up from Five Natural Elements & Three Natural Sources, their Official Taoist Terms are known as Wu Xing (五行) & San Guang (三光).
Wu Xing referring to Gold, Water, Fire, Earth & Wood (金木水火土).

Whereas San Guang referring to Sun, Moon & Stars (日月星).

During Fu Xi (伏羲) aka Master of the Ba Gua, create Ba Gua, he matched the Eight Natural Items into the Eight Directions of the Trigram to form:

Sun – Qian
Moon – Kun
Stars – Xun
Fire – Li
Water – Kan
Wood – Zhen
Gold – Dui
Earth – Gen

Each of the Natural Item is being in-charged by an Official Taoist Deity. The list is as followed:

乾(陽) – Qian – Sun: 太陽星君 Lord of Sun
坤(陰) – Kun – Moon: 太陰星君 Lord of Moon
巽(星) – Xun – Stars: 紫微星君 Lord of Stars
離(火) – Li – Fire: 火德星君 Lord of Mars 
坎(水) – Kan – Water: 水德星君 Lord of Mercury
震(木) – Zhen – Wood : 木德星君 Lord of Jupiter
兌(金) – Dui – Gold: 金德星君 Lord of Venus
艮(土) – Gen – Earth: 土德星君 Lord of Saturn