Mazdamundi always carries with him a gourd containing a handful of dried loci Grubs. These are very potent magical grubs which absorb raw magical power from the ground. When the Mage-lord eats the grubs, he gains the magical energy contained within them. He has to eat the whole gourd-full of grubs to gain a significant effect on his own magical powers, so the grubs can only be used once and are then expended.