After entering the Soul Formation Stage, Zhu Wuyan changed the cultivation technique from the Thousand Poison Technique to the Ten Thousand Poison True Technique.
Cheng Qian's Nascent Soul had also transformed into a stronger Myriad Poison Nascent Soul. It could fuse and absorb more poison, further increasing the combat strength of the Nascent Soul and Zhu Wuwan.
The Ten Thousand Poison True Technique, which was extremely difficult for others, was something that could be solved by throwing in a Breakthrough Stone for Zhu Wuyang.
With the help of a large number of breakthrough stones, Zhu Wuwan had cultivated the Ten Thousand Poison True Technique to the second level. He could fuse and absorb up to 2,000 types of poison.
While Zhu Wuyan was studying the ancient books and earning breakthrough stones, he also absorbed some poison to strengthen his Nascent Soul and Zhu Wuyan's mixed poison.