Zombie-Loan

ゾンビローン

Do you know when you are going to die? Michiru Kita does, as she has the ability to see the ring of death around people's necks. The darker the ring, the closer to death someone is. She notices that two boys in her class, Chika Akatsuki and Shito Tachibana, have completely black rings. Seeking to warn them of their impending demise, she stumbles onto their secret: they are already dead, but they are kept alive due to a contract with Zombie-Loan. Of course, nothing comes without a price. The boys must hunt down and destroy zombies; seeking to use Michiru's "Shinigami Eyes" to help them in their endeavor.

(Source: MAL Rewrite)