Aura

A person's aura is a manifestation of their spirit. Not visible to normal people, Hunters can only see it if they increase the density in how they view the Spirit World. Those who are aware of their aura can hide and show what they wish, and even those unaware of their aura can unconsciously exert control over it by having control of their feelings and being mindful of their limitations. The only time where a person's aura is non-existent is when they are dead, so there will always be part of the aura visible, even if all emotions, feelings, etc. are blocked from others. The only way a person can completely block their spiritual signature is with greater invisibility, which can be read about on the techniques page.