In The Breaker-New Waves after his master broke his ki center he is still able to fight. In fights his level of regeneration is off the charts. He can keep fighting even if he has broken bones. Why is this happening? Is it because of training? Is it because of a medical condition?
His regeneration and stamina have been greatly enhanced thanks to the extremely rare and expensive pill that Lee Shi-Ho (whose clan specialises in such matters) gives him. The pill, Illwallsidan, triggers a tremendous release of ki which most people cannot handle (and often die). But thanks to Chun-Woo's timely assistance, Shi-Woon somehow manages.
Much of New Waves tackles how Shi-Woon goes about restoring his broken ki centre.