I Need to Send off Sixth Brother
The Lightning Emperor Body-Tempering Art and Five Heavenly Lightning Cultivation Technique were two skillsets of the Lightning Imperial Sutra.
If one said that the Five Heavenly Lightning Cultivation Technique was to nurture and store ten different types of Divine Lightning in the dantian, then the Lightning Emperor Body-Tempering Art would be to use all the different sorts of lightning powers to train up one's physical body.
With the strongest body, one would be able to tackle thousands of enemies just by themselves!
Meanwhile, it was not required for all those who cultivated the Five Heavenly Lightning Cultivation Technique to also cultivate the Lightning Emperor Body-Tempering Art, because strictly speaking, both skillsets did not interfere with each other much.