What is the crystal ball in the story used for?

Crystals are generally highly spiritual, so they are usually used as a symbol of spirituality.

If a person with certain spiritual strength has the same magnetic field as crystal, crystal will release considerable power.

Crystal balls are generally used for divination.

But strength has two sides. Different people's minds lead to different uses of crystal balls.

Some people just use it to predict the future or explain the confusion in their hearts, but some people want to use the powerful power of the crystal ball to retaliate or dominate or curse.

As long as your magnetic field resonates with a crystal, it will have a very powerful force for you to see. But it must be used with caution.