Kokoro

Kokoro, an icefish mermaid, is the main conductor of the Sea Train, Puffing Tom, at the station just outside of Water 7. She has a granddaughter named Chimney, who accompanies her everywhere. She was the secretary of Tom, which is possibly why she is now the conductor. Kokoro has been known to pose as a human, hiding her mermaid physique because her tail fin forked in two around the age of thirty and allowed her to walk on land.