Du Jian is a disciple of Tianyun Zi, belonging to the Red division of the Tianyun Sect. His cultivation level is at the Soul Transformation (Ying Bian) Great Cycle Stage.
Due to certain circumstances, he had advanced to the Ascendant cultivation level with the help of Wang Lin then he was forged to be Wang Lin's first Immortal Guard, advancing even further to the Illusory Yin level.
(Source: Baidu Baike, translated)