The Arcane Firmament

The arcane firmament, also referred to as 'the weave of magic', is the invisible network of arcane energies which flow throughout the many planes of existence. It is made up like a rainbow, with each school of magic making up one of the bands colour. Indeed many who can sense it; either naturally or through the use of magic and tools, describe each school as a colour, even if though they can't actually 'see' it.

These bands of energy are what mages and magical items use to power their spells and abilities, they bend around and into them as they are harnessed and released it whatever magnificent display they have been woven into.

The presence of this firmament is critical for casting of spells. Where the firmament is weak spells and magical objects will have a reduced impact, in some places it is motionless or cannot penetrate at all, in which case magic is normally useless.

Inversely there are places where the firmament is particularly strong, or certain schools of magic dominate the others. In these places magic is enhanced but also somewhat unstable.