It wasn't difficult to create a lightning technique. For example, the Three Thousand Thunder Palm Seal was something he could do with ease. However, was it useful? Absolutely not!
Lin Xuan wanted to create his own unique thunder technique based on his own characteristics. This was a long process, and it was unrealistic to achieve it in one go.
Lin Xuan went through the lightning techniques he had recorded in his mind. He did not need to familiarize himself with them now as he only needed to know how to use them. A person would usually only use one or two types of spells. As for the other spells, they were just to provide Lin Xuan with ideas on understanding the way of the lightning techniques.
As he stood up, the bones all over his body cracked. This was the bone refining technique, Thunder Sound, which was used specifically to refine bone armor. For Lin Xuan's bones, he might be able to imprint runes on it. This was his long-term cultivation goal.