I forgot to mention, to any future writers interested in this idea...
Each Alice has one of four possible forms, or shapes.
The form cannot be controlled by the individual, and it specifies how much the Alice can be used, and how often:
Childhood
The Alice will appear in the child normally at the beginning, but disappears as the individual ages into adulthood. Once the person's Alice has completely disappeared, the individual is dismissed from the academy.
Diffuse
The Alice can be used for a long period, at any time, but in relatively low levels of power. Diffuse seems to be the only type that ensures the preservation for all life of the Alice.
Intermittent
The Alice can only be used for a short period, at any time, but at a high level of power. But every time the alice is used, the alice shortens until the time when the user loses his/her alice completely and is let go by the academy.
Limited
The power level of the alice is great and powerful. The alice may be used as often and as much as desired. However, everytime the alice is used, the user's body deteriorates. Eventually, because of the overusing of the alice, the user dies an early death.