Kokoro

Kokoro (ココロ) is the main conductor of the Sea Train, Puffing Tom, at the station just outside of Water Seven. She has a granddaughter named Chimney, who accompanies her everywhere.

Appearance
Her facial features make it look as if she is perpetually smiling regardless of her actual emotions. Her body shape, along with her strange smile, makes her look like a frog. (She is, in fact, an icefish mermaid, though resembles more of a dugong in terms of appearance and shape.) "Kokoro" translates from Japanese as heart, in the emotional sense, or emotion.

Personnality
Kokoro is a heavy drinker, and speaks with a mild speech impediment that gives her dialogue a distinctive ring. While she does have a temper she tends to keep it under control and seems to remind happy no matter what events unfold remaining strangely relaxed and calm. She takes a liking to Luffy and eventually refers to him as the Pirate King. He is very curious about him because the events at Enies Lobby became very intereasting. She came to the conclusion if Tom were still alive he would have helped him just as he held Gold Roger.

Past
She left Fishman Island to support Tom and met her human husband in Water 7. Together they had a son who was 1/2 Mermaid.

Kokoro became the "lovely" secretary of Tom, and a matronly figure to his two apprentices, Iceburg and Franky. She witnessed the deception of Spandam and Tom being carted off to Enies Lobby but was deeply upset about the events of that day.

Present
It was she who revealed to the Straw Hat Pirates, Franky Family, and Galley-La Company foremen the existence of a prototype Sea Train, and she was also responsible for driving the prototype, called "Rocketman," as it sped on its way towards Enies Lobby