[quote=@Lugubrious]
In Fire Emblem, I believe magic is derived from natural ability in an individual and then channeled outward through the use of tomes and staves.
[/quote]

[quote=@Kafka Komedy]
Magic in Bravely Default is a channeled purely through the user, Draining there "MP" which probably stands for some kind of stamina considering some non-magical attacks use it. 
[/quote]

But it doesn't have an external source like in Guilty Gear or some of the Final Fantasy games such as a God of Magic or some form of other realm.

In Bravely Default for instance wasn't there a pillar of pure magical energy that Kaiser tapped into for time travel.