Yoshitsune

One of the seven heroes of the Fire Clan who fought in the great war a thousand years ago.

A half Fire Clan, half Mermaid Tribe hero, known as the "Prince of Water." Although part of the Mermaid Tribe, she has two human-like legs, unlike other mermaids. She dresses as a man, but is indeed a woman. It is unclear why she needed to disguise herself, but it might have been necessary to conceal her Mermaid Tribe heritage. She revered Benimaru as a brother and learned a great deal from him, from manners to tactics, growing as a warrior.

Now, she exists as a spirit residing in the "Holy Sword·Senkaigū Yoshitsune" she created herself. "Senkaigū" is the place where Yoshitsune forged her holy sword.