Kairen

Kairen (カイレン) is a righteye flounder mermaid and an employee of the Mermaid Cafe.

Appearance
Kairen is a mermaid with a somewhat wide face, red lipstick, and long, flowing blonde hair.

Personality
Like all other mermaids, Kairen is kind and caring, and is apparently fun loving.

Abilities and Powers
As a mermaid, Kairen can breathe underwater, speak to fish via sonar waves, and is considered the generally fastest swimmer in the world, along with others of her kind. She also appears to be a skilled dancer.

Fishman Island Arc
Kairen and her friends first appeared in Mermaid Cove, welcoming the Straw Hat Pirates when Keimi brought them there for a visit. When the three princes arrived to inquire the crew's illegal entry into Fishman Island, the mermaids denied the crew was there, hiding them. However, when the crew's presence were made known anyways by Sanji's nosebleed and Hammond's attack, the princes made it clear that they were simply trying to deliver Jinbe's message to Monkey D. Luffy.

After Ishilly and two other mermaids were kidnapped by Caribou, Kairen and the others wondered where they went off to and they had no clue of what happened to them. The only thing they did know was that Ishilly was opening a barrel.

After the civil war between the Straw Hats and the New Fishman Pirates ended, Kairen and her friends danced at the Ryugu Palace banquet in honor of the Straw Hats' victory, and saw them off when they departed to the New World.

Trivia

 * Her name comes from karei (カレイ), the Japanese name for righteye flounder.