Enma Ai is the main protagonist of Jigoku Shoujo: Girl from Hell, who could also be considered an anti-heroine as well. She is actually a spiritual entity who lives with her grandmother in a place frozen in time as it basks in eternal sunset. Ai uses an old computer in their house to receive the names of the clients from the website, and delivers their revenge.
Cute cosplayer from Summer Comiket 2011! It looks like she used her natural hair too! Thanks again to 2chmod for sharing this!