One day earlier.
An ordinary family of four.
The owners of the house lay in pools of blood. Their killer was a murderous maniac—Ryunosuke Uryu.
"Fill, fill, fill, fill—repeat four times... huh, five? Oh, come on, I only missed one—
"—little fill, right? It'll be fine."
Ryunosuke Uryu hummed the summoning incantation under his breath as he used his victims' blood to draw a Magic Circle on the living room floor.
Perhaps a proper ritual ought to be more solemn, Ryunosuke Uryu thought, but that oppressive atmosphere didn't suit his way of doing things.
To him, feeling good mattered more than imitating the atmosphere of a ritual.
"Fill, fill, fill, fill, fill. That's five this time. OK?" He artistically smeared the remaining blood onto suitable spots on the walls.
Then he approached the little boy who was still alive, gagged and bound with rope in a corner. He leaned close to examine the boy's reaction. The boy's tear-filled eyes stared at the remains of his sister and parents.
"Hey, kid, do you think demons really exist?" Ryunosuke asked the trembling child, tilting his head as though deep in thought. "Newspapers and magazines are always calling me a demon. But isn't that strange? One bomb could kill more people in an instant than I've killed all by myself."
"Ah, whatever. Let them call me a demon. But if there are real demons in this world besides me, wouldn't that be insulting to them? That wouldn't be very nice. Is it really okay to go around impersonating them? Thinking about it that way, I guess I have to admit it now. Do real demons actually exist or not?"
"But if a demon really does show up, and we're completely unprepared, wouldn't it be pretty stupid to just have a tea party with