The True Dragon Appears: Eat This Cannonball!

Jiang Chen, a genius weapons scientist from Earth, was framed and killed. When he opened his eyes again, he had become a minor demon cultivator named Xiao Yuer, with a mind full of techniques for controlling souls and refining blood.

The good news: He has extraordinary talent and can hand-build a gauss cannon with demonic pills, or improve a soul-destroying array using the principles of electromagnetism.

The bad news: The demon army is preparing to invade Earth, and he's now just a low-ranking demon soldier.

The even better news: He has secretly made contact with Earth's national security agency, becoming history's first cross-world undercover agent with "the motherland at his back and a demonic pill in hand."

And so the demon world takes a sudden turn:

A Blood Demon elder puzzles over the new "Blood Soul Accelerator": "This thing is fearsome. How does it work?"

Jiang Chen replies solemnly, "It's science."

The young lord of the Soul Demons studies the "Brainwave Shield" that can disrupt mind-reading: "This magical artifact is too profound to understand..."

Jiang Chen hands him the manual. "It's called Maxwell's equations. Required coursework."

With his left hand, he sends the national security agency maps of demon deployments; with his right, he helps the Fiend Demons improve their war puppets. By day, he acts devoted in front of the Heart Demon saintess. By night, he complains to his Earth-based contact, Lin Xue, that "the food in the demon world is terrible."

As the four clans battle, he quietly lays cables and builds base stations, using "demonic technology" to stir up the world. Then the Fiend Demons pour out in force, and the shadow of a dragon from the abyss appears once more. Jiang Chen hefts a magnetic rail cannon a thousand meters long and aims its muzzle at the sky-shrouding demon dragon.

"As a materialist, I kill gods when I see them."