海神、薨、马修、希雅等
海神孕育了最初的生命，有一天，他来到人类部落，居住的淡水井边，误以为海水吸食后，肚腹疼痛不已，诞生下海女——希雅。从此，这井成了连通这个现世与异界的桥梁。希雅，则因为是淡水与海相结合的产物，不能随海回到大洋中。
可每要等二十年旋转周期，井口才能与异世界的河流沟通。为缓解思念之情，海神特意造了一把钥匙。钥匙可以打开海城墙的一个出口，一经打开便是一月时间。城墙开启这段时间，现世、异界可以自由往来，因此海神专门在城墙内训练构建了一支部队：城墙守卫军，特意守护。洞悉世间万物，需要驰骋于大洋之中。离别之际，海神将女儿也一并交由城墙守卫军，代为看管。
希雅的出生，喻义水生动物开始过度向陆地爬行生活。钥匙是全诗的关键。薨，海神的第七个儿子。因不满父亲的统治，杀死了海，并一并处决了其剩下的六个儿子。此时他还并不知道墙内的世界与钥匙的存在。
马修，另一个异界（大洋）的来客。全诗，一处魂归于天，只是一种委婉的说辞，实际上是离开这个大洋，回归到另外一个大洋。主要人物之一。相对城墙内的人类居民，大洋人（局外人）一直都存在。
（注：人物关系。大洋居民，成年后，可以自由出入墙内外两个世界，不受额外条件的限制。城墙内的居民，则不可以。条件限制包括：年龄，钥匙，以及旋转周期——时间的限制。）
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.)