Servamp

Mahiru is a boy who loves simple things and hates troublesome things. He decides to take a black kitty home, but soon finds out that his new pet Kuro may be one of the most troublesome things of all.

Mahiru's pet Kuro turns out to be a servant vampire, or servamp. Mahiru rushes back to school to find out what happened, but his friends do not remember. All Mahiru knows is that a person named Tsubaki is after Kuro...

Mahiru finds out that his best friend, Sakuya, is actually one of Tsubaki's subclass. Why did he get close to Mahiru in the first place? Is Sakuya truly Mahiru's friend or is that another one of the lies that Sakuya hates so much?

Mahiru nearly gets consumed by the power that he had asked for, but a stranger with the servamp of Envy comes to save them in the nick of time. Mahiru realizes that just having power doesn't solve anything and struggles to figure out what to do next.

Mahiru continues to meet new people one after another. Next, he meets a strange boy carrying a coffin at the summer festival as he tries to turn in a lost suitcase given to him by a stranger. People start to take action, each with their own reasons.

Mahiru meets with another suspicious character, a visiting pianist from Austria. He comes to find that the pianist, Licht, is actually the Eve of Greed, Lawless. However, Lawless isn't as friendly as the other siblings Mahiru has met so far.