The source of magic and everything
Mana soak everything, in every corner of the universes. There are place where it is more abundant than others. For example, it is naturally more occuring in the Realm of Ombeline.
Mana is used to do magic, obviously. But it is far from being its sole purpose. Mana, for example, is source of life.
Mana occurs in different forms, whether naturally or after it has been mangled with.
Naturally occuring mana.
Degenerated mana. Found after intensive use of magic.