Werewolf

Werewolves are identical to humans both physically and mentally except during the night where they become half man and half wolf.

Background
Werewolves are identical to humans and it's near impossible to be able to find one in the day, however, at night, they'll transform into bloodthirsty creatures. Werewolves are not welcomed into today's society and are kept locked up for experiments.

Abilities

 * Wolf Form - Werewolves will transform into a werewolf at night, they'll become much stronger and gain better senses.
 * Enchanted Agility - Werewolves are able to generally run faster than Humans.
 * Predator Instinct - They're able to tell when someone is trying to sneak up on them.