Welter is the governing body of Mermaid Island.
Welter was founded by Akira Hiiragi as planned by her mother. She asked Akira to pretend that she's a man so she can be distinguish and be recognize as a leader, The Governeur. They built a castle on Mermaid Island as their base. later Akira intervene in an event where Liberators and Extars abused their powers and try to harm others. In that event he met Kasumi Shigure and her friend Hibiki Kenjo. After successfully saving them, she recruited Kasumi Shiguri for her strength and strong sense of justice. Later Kasumi was given the rank Kommandeur of Welter. Some time in the past they later met Charlotte Scherzen and her group called the Adel. They were the last to join Welter and rule over the palace.