Storm Conjurer - The Guardians, #4

Entering into a treaty with the Olarans, a race who can block the effects of magic, and the Order of Elora, commanded by Imperial sorcerers who were the most loyal servants of Emperor Belack, Empress Hefrask implements the next phase of her plan for the conquest of the Ladorran Quadrant. The second phase involves confronting and removing the primary threat to her plans: Grogaan and the Guardians of the Republic. Grogaan's enhanced abilities in the art of magic, his inner calm and impeccable self-control, are put the ultimate test when one friend is abducted and another killed when confronted by the sorcerers from the Order of Elora and the Hebradon Empire who have united in the fight against the Guardians of the Republic.
Facing opposition from several Guardians, Grogaan ventures deep into Imperial controlled space in the search for knowledge of the Guardians, their magic, and why they failed to retain their postion of trust and power in the galaxy.