Liza thought that she eliminated those Gamma back at the Lake wood fire station, in the early days of the battle, back there, it's not surprising that there is a Gamma existence because Drake was previously building a strong army against the Coven High Chamber, he needed a battle wolf strong enough to fight head-on with the Vampires and lead his army eventually.
Each Gamma can also turn a human which will be the scout during their hunt or in battle, Gamma's have the usual werewolf abilities of quick healing and transformation, Gamma's have a howl ability called 'the hunters cry' commonly when a pack member such as an epsilon or alpha dies, the gamma lets out a loud long howl which instantly switches their epsilons into hunters mode per se. The gamma target is commonly tracked down and killed; the time frame depends on how strong the bond is between gamma and epsilon.
