About Auras

Auras in the use of magic are defined as the space between a mage's soul and their target. As time passes, a mage expands their soul towards their target and the barrier between the soul and the outside begin to disappear, until eventually the mage's soul reaches their target, and they can create a stronger direct guiding line between themselves and their target. You can send a spell to your target through just the aura, but consider say, the use of a fireball spell. The fireball will not just explode on the target. It will explode all over the aura. So you generally use your aura to find your target, and then you send out a guiding line towards your target that actually carries your spell to the target.
There are obviously dangers involved with lowering your outer soul borders. An enemy mage can use that to get behind your own outer soul and get an easy shot in without you knowing. So mages will generally try to have (multiple) (hidden) spectral defenses up, metaphysical walls between their inner soul and the contact point between their outer soul and their aura.

Auras aren't just used for magic. Auras also provide great benefits in martial arts, unarmed or armed. A mage knows generally what happens in their aura, and a great mage will know exactly what happens in their aura. This means that a mage with mediocre sword skills will be the equivalent of a sword master.