Board Thread:General Discussion/@comment-50.165.73.211-20140815010226/@comment-18396318-20140815043614

I think it's pretty simple. Aura is used to use your semblance, but also as a shield. That's why dueling rules end based on aura levels. So Yang becomes stronger as she takes hits, but taking hits also lowers her aura. It isn't so much that there's a hard limit on how strong she can become, but that the same thing that makes her stronger depletes her ability to become stronger.