If you like Ergo Proxy and Battle Angel Alita, Blame! may be a good series for you to investigate.
This first volume of Blame! presents a bleak and grim vision of the future. The world, as seen through manga-ka Tsutomu Nihei's detailed graphics, is dark, metallic and moody. The world is full of violence - hardly two pages can go by without someone/something getting injured or destroyed. This is mostly an atmospheric piece, the story pushed to the background so much as to be nearly non-existent. The hero, or more correctly, the protagonist Killy is aptly named as his main activity seems to be the killing and destruction of the silicoid creatures he encounters in his search for new humans to study in the quest for Net Terminal Genes.