Half human, half wolf, at full power during a full moon. There are three different groups. An Alpha, the strongest of the pack, also the leader. An alpha has red eyes.
A beta, which is your typical werewolf with gold eyes. A beta can become and alpha by killing an alpha.
An omega is the lone wolf, doesn't have a pack and rarely survives, also has gold eyes. A beta or omega can have blue eyes if they have killed an innocent.
Lastly, and certainly the most rare, a True Alpha. One becomes a true alpha by earning it, by doing your best to "protect those who can not protect themselves" (Allison Argent).
