Summary: Four years ago, a large scale disaster in Tokyo claimed two million lives. The remaining thirteen districts of the city were isolated into the Tokyo Barricade Zone. Morisaki Harumi, an unruly kid with great fighting strength, is his familys sole survivor from the incident. One day, in a traffic accident, Haru gets pulled into a world of violence and meets Mana, the girl who turned herself into an ancient sword.

Year Released: 2007
Status: Ongoing

Pretty damn good manga I think. If your looking for something to read I think this is a pretty good pickup.

You can read all the chapters at Mangareader.net. There are currently 39 chapters and the series is currently ongoing.