Kokoro

A fixed, smile-shaped set of features leaves Kokoro looking cheerful no matter her mood, and her rounded, heavy frame gives her a froggish, almost dugong-like silhouette that the Straw Hats find hard to square with the word mermaid. She is in fact an icefish mermaid, her tail having split into two legs at thirty, the change that let her live on land. In her true form she wears a pearl necklace with seashells fixed over her chest. In her youth she was a striking beauty, but Tom's imprisonment and the supposed death of Cutty Flam pushed her into despair and heavy drinking, and she let her looks go.

Drink defines much of how Kokoro carries herself; intoxicated, she slurs in a way that gives her speech a peculiar lilt, while sober she sounds warm and tender. She can lose her temper but mostly reins it in, staying oddly serene through whatever chaos surrounds her. She grows fond of Luffy, eventually calling him the future Pirate King and musing that Tom would surely have built him a ship the way he once built one for Roger. Her trademark cackle opens with a drawn out Na before sliding into a string of ga sounds.

Kokoro left Fish-Man Island to stand by Tom at Water 7, serving as secretary to his crew around the time he constructed the Oro Jackson for Gol D. Roger. She married a human, had a half-merman son, and became a mother figure to Tom's apprentices Iceburg and Franky. When Tom was tried for building the Pirate King's vessel, he won a reprieve to construct the Sea Train, and Kokoro became its first conductor. Spandam's CP5 framed the crew by attacking a judicial ship, Tom shouldered the blame and was taken to Enies Lobby, and after the train seemingly killed Franky she sank into bitterness and drink. She later raised her granddaughter Chimney and the rabbit Gonbe while working as a stationmaster.

Years on, the Straw Hats met her drunk at the station, where she pointed them toward Iceburg and the Sea Train routes. When the crew resolved to save Robin, Kokoro volunteered to pilot the Rocketman, threading it through a wave Luffy and Zoro split open and ramming a giant to clear the way. She revealed her mermaid form to ferry the group through a flooding passage to safety, and after the Going Merry's farewell she returned to Water 7 with them, stunned to learn of Luffy's family ties to Garp and Dragon. As a mermaid she could speak with sea creatures, swim at blistering speed while towing others, and cook ramen and curry; her lone shown move, the Mermaid Kick, launched a Marine flying. After the timeskip she vacationed with Yokozuna and celebrated the crew's reappearance in the news.