Otohime

Queen Otohime (オトヒメ王妃) was the late queen consort of Ryugu Kingdom, the wife of Neptune, and the mother of Fukaboshi, Ryuboshi, Manboshi and Shirahoshi.

Past
Otohime was assassinated in broad daylight about ten years ago, which led to an uproar, but her ideals lived on. She was given a burial in the Sea Forest.

Fishman Island Arc
Jinbe was visiting her grave at the Sea Forest, two years after the Battle of Marineford. When Shirahoshi arrives at the Sea Forest with Luffy and his friends, she pays her respects to her deceased mother.

Trivia

 * She's named after the Japanese sea goddess, Otohime.