The magic system used in this gameworld is styled after the one presented in GURPS: Voodoo. In the ancient world, spells derived from divine powers rather than "mana", and were for the most part subtle, or at least slow. Spirits and divinity were the driving factors, rather than scientific manipulation of a mana force. While Voodoo is written with a Caribbean background in mind, the style is suitable to use in other backgrounds, including this one.
The basic system presented in Voodoo is that spellcasters are Initiated into the spirit world, and learn to perform Ritual Magic. They may then learn various Paths and, later, Mysteries, which enable them to create spell-like effects through the manipulation of spirits (known in Voodoo as loas, but in Twilight as animae or simply spirits). Rituals may be improvised or learned as Hard Maneuvers. Each specific ritual defaults to one of the Paths. The Paths are learned as M/VH skills based on Will.
For game mechanics, advantages and skills, see M. A. Lloyd's Ritual Magic page. I will probably be modifying slightly the precise rituals available, but the ones presented there are a good start.
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