Hitsugime no chaika manga

Hitsugime no Chaika summary:

Toru Acura, an incredibly lazy man with some hidden talents, has been forced by his sister Akari to actually go outside and search for work. However, he is in for a big surprise when he meets Chaika Trabant in the forest, and they are suddenly attacked by a monster! How will they survive? Who is this mysterious girl, and why is she being targeted? From Baka-Updates: "If you work, you lose", such is what Toru mutters to his younger sister, Akari. In this peaceful world, Toru's daily life is filled with despair. One day ,Toru happens to meet Chaika, a girl who carrys a huge coffin upon her back From then on, Toru's way of life changed...