Iso onna are dangerous vampires from Kyushu and Western Japan looking for fisherman and travelers to feed upon. They are closely related to nure onna, despite having no serpentine features at all. Iso onna wander rocky beaches, hunting for prey
Individual accounts of iso onna vary quite a bit when it comes to their appearance. In most cases, they appear as beautiful women who have just come out of the water, dripping wet. Their hair is long and matted, reaching almost all the way down to the sand. Their eyes are heavy with sultry, sexual energy, and their wet clothes stick, nearly transparent, to their skin. From the waist up, they appear like ordinary human women, albeit soaking wet, while from the waist down, they are slightly blurry and transparent, betraying their ghostly nature. In some regions, iso onna are said to have serpentine bodies like nure onna, while in other regions they are said to be large enough to crush ships out at sea, like umi-bōzu. They also have the ability to disguise themselves perfectly as large beach rocks when they don’t want to be seen
When Iso onna appear to humans on sandy beaches, they look like beautiful women, staring far out to sea. When somebody approaches and tries speak to them, they turn around and let out an ear-piercing shriek, which stuns their victim. Then they lashes out with their long hair and drag their prey into the sea, where they drains their victim’s blood with their hair.
On rocky coasts without sandy beaches, iso onna appear sitting on the cliffs and calling out to passersby in an eerie voice. Their victims are mesmerized into walking straight towards them, ignoring the dangers posed by the rocky cliffs. They walk off the cliffs and fall to their deaths, leaving the iso onna free to feed on their bodies.
Iso onna are occasionally encountered far out at sea, but they otherwise act the same as they do on land, capturing their human prey and draining their victims’ blood using their long hair.
Iso onna are most commonly encountered during the holiday seasons of Obon and New Years Eve, when the border between the realm of the living and the realm of the dead can be more easily crossed. They occasionally cooperate with ushi oni to catch their prey.