The Last Mage: Book III of the Mage Tales

Grudge-wielding assassins. Body-snatching demons. Portal-opening crystals. These are tales only a mage could tell . . . if he lives long enough.
I do hope it won’t be the last time we speak, dear readers, for this could be a mage’s greatest battle yet. Even if I do survive it in some form, the Joshua you know may be gone forever.

When a demon takes over your body, there’s nowhere you can run.

The good news is that Joshua and company defeated a 2,000-year-old vampire who sought to rule the human race. The bad news? The demon the vampire wanted to call up is already here—and it’s inside Joshua. If he and his allies don’t rid the world of this scourge, it will cause more horror and suffering than their previous foes combined. Unfortunately, the only apparent solution is as brutal as it is simple:

Kill Joshua, of course.