Are humans evil?

Overview

One day, while Seiya was calling everybody on the phone to tell them "It's me, thank you" on the rooftop of a building, a strange creature with emerald-blue fur, something he had never seen before, descended from the sky. The creature, along with its companions, claimed they had come to exterminate human race. However, through conversations with the humans they encountered, they gradually began to understand each other...