Nika

ニカ

The Medaka Mermaid Quintuplets consist of five small young mermaids who are friends with Keimi. Their names are Ichika, Nika, Sanka, Yonka, and Yonka Two.
Nika has blond hair and a red-striped tail; her top is red, and her hat matches her tail.
The five sisters tend to speak in a unique pattern. Ichika begins by making a standard statement. Nika then repeats it as an exclamation. Sanka states the opposite of the original claim. Yonka questions the original statement. Finally, Yonka Two questions whether the original statement matters. An example of a typical routine:
-Ichika: Luffy is a pirate.
-Nika: Luffy is a pirate!
-Sanka: Luffy isn't a pirate.
-Yonka: Luffy might be a pirate.
-Yonka Two: So what if Luffy's a pirate?
Otherwise, they are cheerful and friendly, and they usually stay close together.
First Appearance: Chapter 608; Episode 527