Plague

The world was left devastated when the fireball fell.

Humanity was not dealt a devastating blow in that instant. Instead, half the world's population vanished overnight.

Ulcers: the effect of infection and ulceration in the surface tissues of the skin and mucous membranes.

Perhaps ulcers aren't the most terrifying thing for humanity, nor are the monsters gradually toppling the pinnacle of human civilization.

Often, the most terrifying thing may be right beside us.

This novel and its characters are entirely fictional. Any resemblance to real people or events is purely coincidental. Do not imitate.