Martial Legacy

A boy named Shi Shan and his little sister were offered as sacrifice to a demon that has been haunting their village. They were rescued by a martial artist who exorcised demons. He took the siblings in as his disciples and taught them the art of cultivation and about the demons that dwell in this world.

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Translated raw sypnosis:

He said, "This world fundamentally should not have demons." And thus, all the lands became peaceful.