Blood Forged — Kathryn Meyer Griffith

An ancient snake-demon lays trapped behind the stone walls of an Incan prison, for centuries demanding blood sacrifices and scheming to escape. Then it discovers a pathway into the world of men, forging itself into a malevolent 357 Colt Python, and making itself capable of incomparable destruction and misery. Through decades it torments, decimates, the unfortunate people whose lives it comes into until a loving married couple, Emily and Sam Walters, have enough love and faith-and the help of a mysterious priest who's much more than he appears to be-to fight against and destroy it forever...and to send it back to hell where it belongs.