There are six boundaries between heaven and earth. Why is the Jade Emperor only the Lord of the Three Realms?

Because heaven and earth are divided into six realms, and one person is in charge, maybe he is too busy, and those three realms are opposite to them, so it is not good to manage them together.

The Jade Emperor was secretly given the jade script by the Yuan God, and began to hold the talisman. He is the owner of the infinite avenue, including the true imperial calendar, the four imperial assistants of the Golden Que, the four holy assistants of the Arctic, and the escort of the great emperor Chen. Its wonderful phase is solemn, the dharma body is supreme, it rules the heavens and commands all saints.

According to the living habits of creatures, there are also divisions. Immortals live in heaven, born on earth, and ghosts walk in the underworld. But in fact, there are six kinds of creatures between heaven and earth, such as God, Magic, Fairy, Magic, Ghost and Man, and naturally there are six realms.

The jade emperor is no different from the emperor on earth except that he has more supreme power and magic power than the emperor. On major festivals on earth, the first thing they want to worship is the Jade Emperor, who is also called God.

Among the other three realms, Fuxi is the leader in charge of heaven. Fuxi was established in the celestial world in the name of fighting against the underworld and became the "Emperor of Heaven". Fuxi invented divination and gossip according to the changes of the universe, and also created words.

On earth, everything is closely related. It also exists in disorder and dispersion, and there is a tradition of the law of the jungle. Animals and plants have been robbed by heaven, earth and people, and have been transformed into human beings, which may be tested or become positive results. The underworld can freely shuttle between the six realms, so it has also caused some harm to the other three realms.

So Fuxi is in charge of heaven, Nu Wa is in charge of the demon world, Shennong is in charge of the demon world, and the other three worlds are in charge of the jade emperor. If he is in charge, he has no ability to manage them.