Neptina is a young mermaid who appears as a supporting character in the anime series Marine Boy. She has long flowing hair and a yellowish green tail, and is typically depicted without clothing above the waist, with her hair positioned to preserve modesty. Neptina is a good friend and teammate of the protagonist, Marine Boy, and works alongside him to protect the ocean. Her primary motivation is to assist Marine Boy in his missions for the Ocean Patrol, often using her mystical abilities to help him when he is in danger.

Neptina wears a large magical pearl around her neck, which possesses special powers. This pearl allows her to locate Marine Boy when he is lost or has been captured by enemies, and she can also use it as a kind of crystal ball to see distant events. In addition, she is able to communicate with sea creatures, a skill that proves valuable in gathering information or enlisting aid during underwater adventures. While she does not engage in direct combat herself, her magic and knowledge of the sea make her an essential ally.

In terms of personality, Neptina is caring and supportive, often showing concern for Marine Boy’s safety. She is not a central fighter but rather a helper who provides guidance and magical assistance. Her relationship with Marine Boy is one of mutual trust and friendship, and she is also known to interact with other recurring characters such as the dolphin Splasher and the young boy Clicli. Over the course of the series, Neptina remains a consistent presence who contributes to the Ocean Patrol’s efforts, though she does not undergo significant personal development or dramatic changes. Her role is largely defined by her function as a magical guide and rescuer, using her pearl to bridge distances and her connection to marine life to overcome obstacles.