Nyai Loro Kidul is a legendary Indonesian spirit, known as the Queen of the Southern Sea of Java (Indian Ocean or Samudra Kidul south of Java island) in Javanese and Sundanese mythology. She is also the legendary consort of the Sultans of Mataram and Jogjakarta, beginning with Senopati and continuing to the present day. Nyai Roro Kidul has many different names, which reflect the diverse stories of her origin in a lot of sagas, legends, myths and traditional folklore. Other names include Ratu Laut Selatan ("Queen of the South Sea," meaning the Indian Ocean) and Gusti Kanjeng Ratu Kidul. The royal house of Keraton Surakarta revered her as Kanjeng Ratu Ayu Kencono Sari. Many Javanese believe it is important to use various honorifics when referring to her, such as Nyai, Kanjeng, and Gusti. People who invoke her also call her Eyang (grandmother). In mermaid form she is referred to as Nyai Blorong. The Javanese word loro literally means two - 2 and merged into the name of the myth about the Spirit-Queen born as a beautiful girl/maiden, in Old Javanese rara, written as rårå, (also used as roro). Old-Javanese rara evolved into the New Javanese lara, written as lårå, (means ill, also grief like heartache, heart-break). Dutch orthography changed lara into loro (used here in Nyai Loro Kidul) so the word play moved the beautiful girl to a sick one - Old Javanese Nyi Rara and the New Javanese Nyai Lara.
Nyai Loro Kidul is often illustrated as a mermaid with a tail as well the lower part of the body of a snake. The mythical creature is claimed to take the soul of any who she wished for.Sometimes Nyai Loro Kidul literally can be spoken of as a "naga", a mythical snake. This idea may have been derived from some myths concerning a princess of Pajajaran who suffered from leprosy. The skin disease mentioned in most of the myths about Nyai Loro Kidul might possibly refer to the shedding of a snake's skin.The role of Nyai Loro Kidul as a Javanese Spirit-Queen became a popular motif in traditional Javanese folklore and palace mythologies, as well as being tied in with the beauty of Sundanese and Javanese princesses. Another aspect of her mythology was her ability to change shape several times a day.Nyai Loro Kidul in a significant amount of the folklore that surrounds her-is in control of the violent waves of the Indian Ocean from her dwelling place in the heart of the ocean. Sometimes she is referred as one of the spiritual queens or wives of the Susuhunan of Solo/Surakarta and the Sultan of Jogjakarta. Her literal positioning is considered as corresponding to the Merapi-Kraton-South Sea axis in Solo Sultanate and Yogyakarta Sultanate. Another pervasive part of folklore surrounding her is the colour of green, gadhung m'lathi in Javanese, is referred to her, which is forbidden to wear along the coast of Java.
Panembahan Senopati (1586-1601 AD), founder of the Mataram Sultanate, and his grandson Sultan Agung (1613-1645 AD) who named the Kanjeng Ratu Kidul as their bride, is claimed in the Babad Tanah Jawi.One Sundanese folktale is mentioned about Dewi Kadita, the beautiful princess of the Pajajaran Kingdom, in West Java, who desperately fled to the Southern Sea after being struck by black magic. The black magic was cast by a witch under the order of a jealous rival in the palace, and caused the beautiful princess to suffer disgusting skin disease. She jumped into the violent waves of the Ocean where she finally cured and regain her beauty, and the spirits and demons crowned the girl as the legendary Spirit-Queen of the South Sea. A similar version of the story above mentions that the king (at the time), having her as the only child, who is planning to retire from the throne, remarries. Having a queen (instead of a king) was forbidden. The king's new wife finally gets pregnant, but, because of jealousy, forces the king to choose between her wife or her daughter. There was an ultimatum. If he chose his daughter, then her wife would leave the palace and the throne would be given to what would later become the queen. If the wife was chosen, the daughter would be banned from the palace and the new, yet to be born child, would be king. The king solves this by ordering a witch to make his daughter suffer a skin disease. The daughter, now banned from the palace, hears a voice that tells her to go to the sea at midnight to cure her disease. She did, and vanished, never to be seen again. Another Sundanese folktale shows Banyoe Bening (meaning clear water) becomes Queen of the Djojo Koelon Kingdom and, suffering from leprosy, travels to the South where she is taken up by a huge wave to disappear into the Ocean.Another West Java folktale is about the Ajar Cemara Tunggal (Adjar Tjemara Toenggal) on the mountain of Kombang in the Pajajaran Kingdom. He is a male seer who actually was the beautiful great aunt of Raden Jaka Susuruh. She disquised herself as a psychic and told Raden Jaka Susuruh to go to the east of Java to found a kingdom on the place where a maja-tree just had one fruit; the fruit was bitter, pait in Javanese, and the kingdom got the name of Majapahit. The seer Cemara Tunggal would marry the founder of Majapahit and any descendant in first line, to help them in all kind of matters. Though the seer's spirit would have transmigrated into the "spirit-queen of the south" who shall reign over the spirits, demons and all dark creatures.