I Cultivate Immortality by Living Off Others in a Supernatural World

I transmigrate to a high-martial world and become an old man on the brink of death. To stay alive, I marry a corpse in red from the back hill. She sweeps and cooks for me, and even instantly kills my enemies. But every night we share a bed, I’m afraid she’ll turn me into one of her kind. Then one day, the Ten Great Immortal Sects surround my home. She floats out, and ten thousand ghosts bow to her. That’s when I realize my wife might be the… Evil God Ancestor they’ve worshipped for a thousand years.