A dark bronze booklet cast with the thunder pattern. Right-click to learn the Purple Heaven Thunder Saber and its first technique, Thunder Descends. Used up when read.

It only teaches from the Qi Condensation realm: below it, you are told you are too weak, and you keep the manual.

The sky gives it, once per player. In the Overworld, during a thunderstorm, stand under the open sky with a greatsword in your main hand, within 2 blocks of a lightning rod that is itself open to the sky. You are told The storm turns toward you. Hold your blade high...; keep all of it for 6 seconds and a bolt strikes the rod and runs through you without burning. The manual goes to your inventory, or falls at your feet if it is full.

The storm only answers from the Qi Crystallization realm: below it, it passes you by and says so.