Verdict on Crimson Fields — M.C. Planck

An engineer upsets the rigid social order of a medieval-level magical society as his attempts to return to our world amass him more power--and more enemies.

The continuing adventures of Christopher Sinclair, mechanical engineer turned priest of war.

Christopher is sent north to avenge the destruction of County Nordland, but murderous dragons and genocidal goblins are the least of his worries when his allies keep promising to kill him first. His advancement has not gone unnoticed, and even powers outside the realm show an interest in his career. As always, the price is high, and Christopher is not the only one who must pay.