Black God Vol 3

Black God by Dall-Young Lim and Sung-Woo Park. An Action manga rated Older Teen, published in English by Yen Press.

Keita Ibuki's ordinary life ends when he meets Kuro, a mysterious girl with a big appetite and an even bigger sword. She is a Tera Guardian who hunts doppelgangers, and after an accident ties their fates together, Keita is dragged into her dangerous world.