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. She wears a white, revealing bikini, with a purple stripe-like pattern on it, that looks similiar to the marine's "MÖWE" logo.

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

Abilities and Powers
Being a mermaid, Kairen has several abilities unique to her race. It is not yet shown but she may have the ability to talk to fish and call out to them using sonar waves, which is one of the basic abilities found in all mermaids and some fishmen. Apart from the ability to breathe underwater, as a mermaid she also has the ability to swim very quickly at speeds much faster than the flying fish used by the Flying Fish Riders. However, like any mermaid, she is vulnerable on land.

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.