[@FlitterFaux]

As far as I remember, Aura is treated as a "fuel source" of sorts for the Semblance. It's kind of a stand in for ki, chi, chakra, feng shui or whatever the hell you want to call "soul energy" in your favored shonen series.

For what it's worth, we do also play a little fast and loose with the relationship here. I think Luke's Healing Blood is still stuck in the realm of "its easiest to just roll with it"...