A slight murderous impulse
I understand what you mean, but I can't really think of much that fits that description. Gurren Lagann comes to mind, though it's not exactly the same. Shattergraves might have the best recommendation with Uninhabited Planet: SURVIVE. Shiki is a really good anime where the inhabitants of a small town start dropping like flies, and some of the residents begin looking for answers, but it's also not quite the same.
I'll try to think of something else.
"I teach Karate, Judo, and Sumo on the Internet. Come at me." -- Professor Ueda