Hell Girl Vol 2

From the Del Rey Manga edition

The Hell Girl is the ultimate avenger. Go to her website at midnight, enter the name of your tormentor, and the Hell Girl will destroy your enemy. Some who turn to the Hell Girl are evil (the figure skater who'll stop at nothing to win); others are good people at the end of their rope (the girl who saves her sister from an abusive nanny). But the price of revenge is the same for all: eternal torment in hell!

Source: Anime News Network Encyclopedia