The Fittest

"You've seen them?" The newcomer wailed, her eyes darting back and forth frantically.
The leader of the group stepped forward, his face dimly lit by the single bulb in the room. "We've all seen them." He gestured to the motley mix of people around him.
A sob of relief tore through the trembling girl's chest as she threw herself into the leader's arms; he fumbled to catch her.
"What are they?" She cried.
"We don't know."
The girl looked up, her desperate gaze locking onto his pained one and she whispered, "How do we stop them?"
A shudder coursed through the leader's body as he remembered what had happened to him when he'd tried to intervene with the Fittest's actions.
His eyes watered profusely and he lowered his head, stricken with grief and shame.
"The answer's simple," he replied in an even quieter voice. "We don't."

I'll add a better description later. I'm too tired right now. XD