After placing the Soul Locking Gu array into Patriarch Yao Yue's soul, as long as the memories of the lower part of the Nirvana Ceremony appeared in Patriarch Yao Yue's mind, Zhu Wuwan would be able to read them.
However, if Patriarch Moondevil didn't recall this information, it would be hidden in the depths of his soul, and Zhu Wuwan wouldn't be able to read it.
The Soul Locking Gu formation could only read shallow memories, which was Patriarch Demonic Moon's real-time memories. It could not read deep memories at all, and Zhu Wuwan did not dare to read them either.
The lower part of the restriction array formation of the Nirvana Ceremony was deep in Patriarch Moondevil's soul. That was also the strongest part of the restriction array formation. With the Soul Locking Gu formation that Zhu Wuwan had set up at the moment, it was impossible to read it.
Even if he tried to read it by force, he would be discovered by the restriction array and bring disaster upon himself.