Raptors-The Beasts' Beginning

Raptors, giant wolf-like creatures created by the government to be used to 'keep the peace and prevent more wars', have broken free of the labs they were created in. They run freely through demolished cities, forests, open fields, and other dark places, searching for humans to devour and destroy.
The few civilizations that survived the first attack of the feral expirements-gone-wrong, began building underground cities, rarely going to the surface.
When a child is of 15 years old, they are sent above ground to make a living for themselves. Regardless of age, some people are simply exiled, no longer allowed to take refuge in the subterranean civilizations.
In the recent years only one person has been exiled... A girl named Autumn. This girl leaves no traces of her presence anywhere, one of the reasons she's believed to be long dead. She is, however, alive, and has developed a toxin strong enough to kill a full grown Raptor.