Guangchengzi is the Chan immortal of Peach-Source Cave on Mount Nine Immortals in Investiture of the Gods. One of the Twelve Golden Immortals, he carries the Fantian Seal and wears protective Eight-Trigram robes. In the Ten Absolute Formations he enters the Golden Light Formation, shields himself from its mirrors, smashes them from beneath his robe, and kills Golden Light Sacred Mother with the descending seal.
He is also master of the Shang prince Yin Jiao. Guangchengzi rescues the condemned youth, trains him, and later gives him a fangtian halberd, Fantian Seal, Soul-Falling Bell, and Male-and-Female Swords for the descent to Zhou. When Yin Jiao breaks his oath and uses those gifts against Xiqi, the teacher must help recover or neutralize his own arsenal. Their relationship makes transmission itself dangerous: a master’s treasures magnify both the disciple’s promise and his betrayal.
Later Guangchengzi defeats Fire Spirit Sacred Mother with the Fantian Seal and revives the wounded Jiang Ziya. He then carries her Golden-Haze Crown to Biyou Palace, attempting to return it respectfully; hostile Jie disciples surround him, and his repeated entries into the palace deepen the quarrel that leads toward the Immortal-Execution Formation. The square seal, clouded cave, patterned robe, and tense passage between rival schools show him as both formidable combatant and senior envoy caught inside a widening religious war.
