So basically there was an infection 2 or 5 days ago that was spread to humans and the demons gone missing, some of the slayers got infected due this infection*

There's 4 stages of infection 

Stages 1: nothing will happen at first but you start to feel bit weird

Stages 2:you'll get burn eyes and you'll get sick 

Stage 3:you'll get black eyes and have sharp nails, and sharp teeths and your jaw line will be broken

Stage 4:...**you're one of them**

Stage 5: your not human....