Xuanqing Guard

In the old Jin dynasty, evil spirits and ghosts ran wild, so the Xuanqing Guard was established to oversee the world, root out traitors and evil, and kill evil while supporting the righteous Dao.

Shen Hao transmigrated to this world and spent four years climbing from an ordinary soldier in the Xuanqing Guard to a small-banner officer, but given his background, it was almost impossible for him to rise any further.

Then one day, he suddenly discovered that there was a dragon inside his body: the ancestor of ten thousand dragons, one that feeds on living souls and immortal spirits! Every time he killed an enemy, this dragon would leap out to tempt him into devouring the other side's soul, demon core, or evil core, and his cultivation began to soar wildly as well.

...

Shen Hao: I'm just handling cases, so how did I end up invincible?