What is the meaning of evil spirits in death divination?

After her sister stabbed her mother to death, she put her sister in a secret room and dragged her mother out. Then the police came and were sent to a mental hospital. After being sent back to the ward, she uncovered the carpet, drew a divination board on the ground, and summoned her sister with glasses.

At the end, many, many years later, someone pretended to be my sister's niece to visit her, followed by the content of death divination 1, which is actually a prequel.

This paper analyzes the reason that it may bring temporary convenience through improper means or using evil spirits, but it will eventually be murdered by evil spirits.