The four famous hunters had already been hidden, but they reappeared because their master Zhuge Shenhou was killed. Shangguan Cang Qiang assassinated Shenhou and successfully seized his throne, and then revealed his ambitions, and he controlled the emperor with drugs, trying to force him to surrender the throne. The four great immortals learned of his conspiracy, obstructed it, and vowed to fight with him to the end and crush his dream of becoming emperor.
More info