Magical power is a gift, in that it enables those who wield it to accomplish things that would otherwise be impossible. Those who possess this gift can move themselves across vast distances instantly, lift objects with their minds, incinerate dozens of men with a gesture, and perform other superhuman feats.
The Gift stat is a general reflection of how skilled your protagonist is at consciously and deliberately manipulating arcane energy. He might express this through classic, external manipulations like fireballs and conjured elemental creatures, or he might internalize the energy, becoming a devastatingly fast and powerful warrior.
All wizards start with a Gift score of three to represent their training at the hands of The Order. A score of three means that your protagonist will always roll three Gift dice whenever he attempts something relating to the arcane. By comparison, mundanes have a Gift of zero. Especially devout members of The Mother’s Church, devotees of the Knights of the Mask cult, and monks who have trained at the Great Monastery may have one or, in rare cases, two points of Gift, so a protagonist with a three is exceptional.