Over 400 years ago in a quiet village in Japan, Ai Enma was born.She had always been an outcast in the small farming village, her looks scaring many. The only friend she had was her cousin Sentaro, who often protected her. Ai was undoubtedly special, and a group of boys claimed she had revived a dead butterfly with just her hands. Although she claimed it simply wasn't dead, she had a gift.
The village had gone through many hard times, and every so often they'd sacrifice a seven year old to the mountain god to grant good harvest. This time came, and Ai was chosen. Refusing to accept this, Sentaro agreed with Ai's parents that they had to hide her before she could die, and so he hid her in the forest. She lived in a small hut barely big enough until she was thirteen. One day she left the hut with Sentaro so she could take a bath in a small lake they had found. They were about to return her back to the hut when the villagers had found them. That year the harvest had failed, and they believed it was their fault. Capturing Sentaro, they forced him to watch as they beat and assaulted her. She was eventually sacrificed, and was horrified to see Sentaro push down the first shovelful of dirt, although he was forced. In her dying moments she cursed the town, proclaiming that she would torture them for doing this to her.
Sometime shortly after Ai's ghost returned, burning the entire village to the ground. Sentaro would survive though, having left the town before she returned. An entity often know as The Spider or The Master of Hell appeared, telling her she had sinned, as her parents and others who had protested her sacrifice were also killed. To repent, he made her Hell Girl, and used the souls of her parents to guilt her into it. Should she stop her job or have a violent burst of emotion her and her parents would be dragged to Hell.
Over the years the means of contacting Ai differed, but the base concept remained the same. You must contact the Hell Correspondence, and she will appear.In simpler times you had to put a letter with the name of the person you wanted to curse into your mailbox at exactly midnight, though in modern times you simply have to look up Hell Correspondence at exactly midnight to access the site, there you enter the name of the person you wish to die. Ai will give you a straw doll, and tell them that if they pull the thread that person will die. There is a price however. The person will be dragged to Hell as requested, but the person who contacted Ai will also be sent to Hell once they eventually die. Many accept the cost and use her services.
Ai works with three others to make up the team, mainly Wanyuudou the old man, Hone who appears as a young woman, and Ren who often appears in his late teens. All of them also have troubling pasts, and namely work for Ai, not The Spider. In fact, they often disrespect The Spider in private, resenting how he guilt's Ai into this position.
Ai noticeably does not say much, even to the rest of her team. Most of her words will be answering questions from her clients (or sometimes the others, they aren't afraid to question her) or wise words of wisdom. She resents her position as Hell Girl, but no matter what she knows she can not give up the title unless The Spider allows her to. Over the years there have been changes to the Hell Correspondence team, namely the inclusion of Kikuri, who appears in the second season and often wreaks havoc. While Ai seems indifferent most times to Kikuri, Hone and the others dislike her strongly, and there is often a lot of banter back and forth, particularly since Kikuri has a knack for somehow knowing things about the others, such as knowing that Ren was the soul of an ancient katana, a fact only Ai was aware of. At the end it is revealed that she is not exactly human, and although she has a soul her body can be taken over by The Spider, casting confusion on how much of the horrible things she did where actually from her or from The Spider.