Board Thread:General Discussion/@comment-25266931-20170112165458/@comment-26397825-20170117021546

As Ark said, creating a econdary denser shield over the body wouldn't help. You don't increase your aura capacity doing that, you just make it easier to chip away. Each time aura blocks a strike, it is used up. Once it is all used up, that's when actual damage is done to you.

Sun was hurt not because he didn't have sufficent aural armour or an advanced aura technique protecting key parts of his body but because he ran out of aura entirely. Maintaining 4 clones for an extended period of time when the most he had made previously was 3 which only lasted a few moments was seriously taxing on his aura reserves. He pushed himself too far trying to help Blake, and she didn't take the opportunity anyway and he paid the price for it.