It is said to appear as a human woman with long black hair and dressed in a white kimono. She also has two horns, black fanged teeth and a blue complexion. The blue skin may be attributed to the blue lamps burned and she may instead have the traditional chalk-white face.
It's personality isn't well known, but one would have to believe that a ghost who enjoys answering the call of brave - and not-so-brave - Humans in need of a fright would find some sort of enjoyement in scaring othersé
Ao-Andon is the Japanese equivalent of Bloody Mary. During the game called Hyakumonogatari Kaidankai (百物語怪談会 or 100 Ghost Stories) 100 lanterns covered in blue paper were lit to add to the eerie atmosphere. After the completion of each story a lantern is put out. After finishing all 100 stories and extinguishing the final lantern the blue lantern ghost will appear.
The game once used candles, but in the better-known version they were replaced by specially prepared blue lanterns to give the gathering a more mysterious feel—an early form of mood lighting. These lanterns, called andon, consisted of paper panels in bamboo frames set over candles or oil lanterns. Normally the paper was white, but for Hyakumonogatari Kaidankai gatherings the white paper was replaced with blue.
The game got even more sophisticated over the centuries, and even a little bit more lazy. Instead of lighting a hundred lanterns, sometimes oil lamps were prepared with specially made wicks that counted down from one hundred. Which each story, part of the wicks was cut, bringing the light down until the final cut. Some games would place the lantern in a room away from the main gathering place, next to a mirror. After each story, the storyteller would have to walk alone into the room, cut their wick and then stare into the mirror.
Many gatherings actually cut their event short after the 99th tale, with no one being brave enough to walk into the room for the final story.