Mad Demon

 is a weapon in SINoALICE.

Weapon Story
There once was a man who was obsessively clean.

Hoping to avoid contact with other people, he only set foot outside his home at night. But his efforts were for naught, as others walked the main street no matter how late he went out.

He couldn't stand it.

To him, humans were the dirtiest creatures alive.

Before long, he was killing anyone that he came into contact with.

"This world needs to be purified," he murmured.

In time, people stopped going out at night. And yet, the man still wasn't satisfied. "Right...there's still one left." These were his last words before he killed the only person left that his eyes couldn't see.