- Ocean god, Hong, Matthew, Sea and others
- The Ocean god gave birth to the first life. One day, he came to the human tribe, living by the freshwater well, mistaking the sea water for food, and suffered from stomach pain. He gave birth to a sea girl – Sea. Since then, this well has become a bridge connecting this world and the otherworld. Sea, because she is a product of the combination of freshwater and sea, cannot return to the ocean with the ocean.
- But every twenty years of rotation cycle, the well mouth can communicate with the river in the otherworld. To ease the longing, the Ocean god specially made a key. The key can open an exit of the sea wall, which is one month long once opened. During this time, the world and the otherworld can come and go freely, so the Ocean god specially trained a team in the wall: the wall guard army, to protect it. To understand everything in the world, you need to gallop in the ocean. At the time of departure, the Ocean god also handed his daughter to the wall guard army for custody.
- Sea’s birth symbolizes that aquatic animals began to crawl on land excessively. The key is the key to the whole poem. Hong, the seventh son of the Ocean god. Dissatisfied with his father’s rule, he killed the Ocean and executed his remaining six sons. At this time, he did not know the existence of the world inside the wall and the key.
- Matthew, another visitor from another world (ocean). In the whole poem, returning to heaven is just a euphemism for leaving this ocean and returning to another ocean. One of the main characters. Compared with the human residents inside the wall, ocean people (outsiders) have always existed.
- (Note: The relationship between characters. Ocean residents can freely enter and exit both worlds inside and outside the wall after they grow up, without being restricted by additional conditions. Residents inside the wall cannot. The conditions include: age, key, and rotation cycle – time limit.)