The Butcher of Souls by T.L. Cerepaka

When the most powerful mage in North America hires me to solve a case, I accept it, because I need the money and know I'll get paid well if I solve it.

Turns out that one of the most dangerous magical criminals ever--whose power equals that of the Master Mages themselves--has escaped from prison. His goal: Kill my grandfather, who helped put him behind bars decades ago and who is also currently too old to defend himself.

The case seems simple enough, but as always, there is more to it than meets the eye. If I can't figure out what the criminal is really trying to do, paying rent this month will be the last of my worries.