Lee Sin Burned Himself Up And Only His Eyes Were Affected

Ok fine, he's actually an alien from outer space who killed many soldiers in battle, but killed a little boy on accident and burned his eyes because he felt really guilty. His eyes were the only thing in his indestructible body that were able to be destroyed. He then used his alien powers to turn human and eventually founded kung fu. He then became a monk and dedicated his life to a newfound purpose, to teach and protect the innocent.

at least they made unable to wear boots.