Citizen Magus by Rob Steiner

Remington Blakes is a magus from an alternate 21st century where magic powers the world. And he has a big problem.

His former mentor, William Ford, stranded him in ancient Rome without knowing how or why. Well, a guy has to eat, so he ekes out a living as a magus-for-hire among Rome’s plebeians. He calls himself “Natta Magus” since his real name sounds too Germanic to the discriminating Romans.

When Natta learns that Ford has conjured daemons to kidnap a senator’s young daughter, he jumps at the chance to track Ford down. Natta chases him to Rome’s Germanic frontier to not only rescue the child but learn the terrible secret behind why Ford left Natta in ancient Rome.

An exciting start to the Journals of Natta Magus, a series for fans of Harry Dresden and Roman fantasy.