Previously, when he heard outside that the Underworld possessed thunder techniques, he guessed that there should be thunder technique manuals in the treasury. Upon entering, he immediately used his spiritual force to search, and just as he expected, he found this copy of the "Yuxiao Thunder Technique".
He flipped open the pages and began to browse roughly. After reading a few pages, he was both surprised and delighted.
The "Yuxiao Thunder Technique" was divided into two parts: the upper half used oneself as a cauldron to absorb thunder Qi to strengthen oneself, and the lower half was the thunder array outside.
Chapter 729