In fairy tale, it appears that the youngest or the only child will be the protagonist of the story because it may do the significances for the story.

The Little Mermaid eyes color are the same as the sea which demonstrate the similarity between the mermaid soul and origin. All her life, all she knows is the sea and despite the beauty of blue color, it may represent that her eyes are "blue" (sad) with everything she has.

The age of 15 represents adulthood and maturity of a girl. It can be understood that at this age, a girl can get married.

Addressing the wealth of the sea kingdom and the similarities between the architecture between the surface and the sea world which the sea also has fancy and tall buildings.

Although in the story the surface and the sea kingdom coexist and the surface people do not know about the kingdom in the sea, Andersen still give the kingdom a hierarchy with a king, princesses and subjects.