"Express Delivery to the Grave" or "Ken Tenma: Serial Killer

Let's not beat around the bush: As far as the Corps are concerned, Clones are property are slaves. He may have escaped his fate, but countless of his brothers, his twins, remain forced into a servitude. And if that wasn't enough, nobody cares. He meets a whole cast of characters, each one of whom is too busy with their own petty lives to see the industrial horror going on often within their sight. Then someone who will remain nameless starts going on about the "plight of the downtrodden," ignoring the most downtrodden of all, and something inside him just snapped. They will pay, every single one of them, and with a new buzz-sawed monstrosity, he knows just the way to do it.