Therefore, this martial arts technique was quite useless, so much so that Xu Yang hadn't even practiced it.
It wasn't until he entered the Black Water World and devoured the school of electric eels, obtaining the innate divine ability "Thunder-Driving Lightning-Lifting," that he had an epiphany.
The reason the Heavenly Thunder Tempering technique was useless wasn't just due to the martial arts itself; the problem also lay with "thunder and lightning."
His understanding of thunder and lightning, his research into it, and his control and use of it were far from thorough, which naturally rendered the Heavenly Thunder Tempering technique he created quite useless.
However, there was nothing wrong with the basis of this technique; indeed, thunder and lightning could temper the body, and the effects were extraordinary.