Hell Girl Things

A Kimono is a traditional piece of Japanese clothing that is worn by women, men, and children alike. They are normally long robes with long and wide sleeves.

Pigtails are a hair style in which (typically women) wear their hair parted down the middle with two ponytails coming off the back of their head. Pigtails are very prevalent in Anime/Manga

The character is wearing school uniform. Most probably he/she's a student.