Grand General - Chapter 0

From what I’ve gathered after all this reading, is that high-level cultivators can decide what age they want their body to be, most cultivators have a young ‘peak age’ body due to cleansing all the impurities out of their bodies.

Now that the MC has given up his responsibilities perhaps subconsciously he has returned to a younger state of mind and his body is following those changes, his power however should remain the same as his external shell may have changed but I doubt his dantain has.