Feeling of being perfected by Thunder

He could feel the golden thunder drowning him and what came after was pure comfort. After all the body was recovering fast, and when his muscles had regrown, he heard a sound from the body. 

Om'

This was what he felt all over his body as some fluctuations started to manifest from the cells and then spread all over. His longevity art broke through. But more than just that, the seedling he had created on his left side of the dantian started to absorb the purple energy being generated by the body at a faster rate and developed into a small sapling with a few leaves.

It was also an ascension of the body to the entry stage of the world tree stage. This was powerful however and he was certain that to make improvements, he would need more chances in the future which were not easy to get hands on.

Just like this tribulation that has been giving the body energy cannot happen every time.