Shinobu Yoshioka

Mato just got into junior high school and someone catches her eye-her classmate Yomi. Although being total opposites, they become friends and their friendship blooms.But in the second year at the school they get placed in separate classes and they begin to grow apart. But somewhere simultaneously... In another world,a young girl,blue fire residing in her eyes,Black Rock Shooter faces another young girl; this one holding a jet-black scythe, Dead Master, and a battle to the death begins to unfold (anidb.net/)

It isn't the world you know. There wanders a girl with jet-black hair, ebony clothes, and a strikingly blue, glowing eye. Her name is Black-Rock Shooter. With a huge cannon in hand, she throws herself into a fierce battle... Meanwhile, in another world, middle-school student Mato Kuroi is drawn to Yomi Takanashi, her classmate with an unusual family name. Mato does her best to talk to Yomi, who just won't open up. (myanimelist.net)