Golden Trigram's memories had been 'sealed' before, and he knew this very well---because he didn't have any memories before he joined the Heavenly Court!
Not long ago, when he was inheriting the position of the Heavenly Emperor, the Heavenly Emperor had personally answered his doubts about sealing his memories. According to the Celestial Thearch, he was once a disciple that the Celestial Thearch had secretly taken in before establishing the celestial heavens. His cultivation techniques, knowledge, and methods were all taught by the Heavenly Emperor. This was also the reason why he was unable to take the final step on the path to immortality. This was because his path was actually the path of the Heavenly Emperor! Under the premise that the Celestial Thearch had a master, he could not attain immortality.
