Shikabane-Gatana is a Manga/Manhwa/Manhua in english language, ACTION series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.nl fastest updating comic site. The Summary is

The "battle action" manga centers on Tsuranuki Tsutsuki, a middle school boy who lives a happy life despite slightly strange family circumstances. But when a great disaster strikes, strange zombie-like creatures kidnap his younger sister. To find the whereabouts of his younger sister, Tsutsuki heads to monster-infested Tokyo, and there has a chance encounter with a high school girl wielding a mysterious sword.