"Aura Manifestation" or "Aura Constructs" are often talked about but rarely witnessed. There is good reason for this. Every second that magica is used to form and control an Aura is a second that magica is being used and wasted.

Ideally for defense you want to create a thin rigid plane of magica, and for offense you want to make it either inflict blunt force or piercing damage, depending on the target.

However, Auras take on the shape and to some extent the INTENTION of the wielder. This is a massive and constant drain. 

There are upsides to this, if the cost is ignored. An Aura can both inflict damage and defend at once, and advanced Aura constructs seem to develop a will of their own, aiding the wielder without needing active input. 

Wizards have shown it is possible to set up relays to other Wizards as well as energy sources, and through this have been able to showcase advanced Aura control.

However, time and again it has been demonstrated that for the same amount of energy expenditure you can use the energy in more efficient ways.

-Advanced guide to Magic and its practical uses