Two kinds of werewolf have been shown, the pure and mutts, like dogs. 
Mutts are quite different to purebreds, they behave (even in their human form) and look more like dogs, they also seem to lack the aggression and anger that purebreds have, they also are shown to be weaker. Unlike purebreds they transform every night, lack or have weaker versions of the powers and transmit the curse by kissing, they also transform near instantly. Though the effects can be reversed with a potion.
When mutts transform, they see everything in black and white.
Purebreds however a much more like werewolves in the legends, there are three forms.
- The human form
- A mid wolf form
- A form where they are full wolf
It is the full wolf form that they are most powerful. However (like the werewolves in the legends), they lose control and become more violent, aggressive and dangerous (plus they lose a lot of their intelligence) while in their full wolf form.
Their transformations are different too, whiles mutts transform near instantly and painlessly, the purebreds' changes are slower and more painful. First they start sweating and look and act they are extremely stressed, behavior changes and then their eyes glow yellow and their teeth turn to fangs, their face morphs and then their arms and then the rest of their body, during which they scream in pain, and finally howl at the moon. They normally only transform when there is a full moon. Although intense anger or rage, will speed up the transformation, so it happens also near instantly if a full moon is present or temporarily transform them into their mid form if it isn't.
Their behavior is also much more like a human's (although they still have the odd dog quink here and there) in both their human form and their half-wolf form, their behavior is exactly like a enraged wolf when in there full-wolf form. They also don't pass the curse by kissing, and it's implied that to do that they bite beings, like in the legends.
They are also shown to have an incredibly bad temper.
It's possible to cure Mutts with a certain potion, its unknown if it would work on Purebreds, but based on a purebreds abilities and information, it's unlikely.
Werewolves are very proud, impulsive and loyal beings. They take great pride in their magical abilities and believe that other magical creatures can't understand a werewolf like a werewolf. Several times they are shown to have horrible tempers.
Werewolves prefer a cave as a residence, and very wealthy families have very luxurious caves. Werewolf culture, though largely unknown, seems to have a strong connection with seasons and moon, such as the Moon Autumn Celebration. 
Werewolves are shown to have quite great appetites, Mason was able to eat all the ham in the Subshop, quite quickly and showed no ill effects afterwards. They also seem to eat humans, as Mason ate Dean whole, and once Mason's family's feast was destroyed, his relatives planned to eat Alex.
Due to their great power, ferocity and temper, werewolves are shown to be feared by many, including Cucuy's, who themselves are feared by humans.
Magical Powers & Abilities
They are also extremely powerful, mostly in the full wolf form, their powers are:
- Shapeshifting: Werewolves' primary power enabling them to change between their human and wolf form.
- Enhanced Senses: Werewolves can hear, smell and see better than ordinary humans.
- Inhuman strength: They were shown to be incredibly strong, able to jump quite a large distance from a standing position, and match blows with a vampire.
- Great stamina: Mason was able to carry Alex the entire Journey home, from the fake government lab, admittedly with probably breaks at points along, and was still reasonable okay be end of it, all while still in his human form.
- Incredible Speed, Reflexes and Agility: All demonstrated during the fight with Mason against Juliet and Justin.
- High Pain Resistance and Durability: Shown by the fact that during the fight, no matter what hit Mason, he did not react, whether it was punches, kicks, swipes and Justin's spell that was supposed to either kill or knock him out. Despite this they are not invincible and can be defeated, for example by a well trained fighter, with lots of experience 
- Greater Life span: Werewolves can live for centuries. 
- Canceling Powers: If a werewolf scratches a vampire, then the vampire will loose all vampiric powers and will reveal their true age. If a vampire bites a werewolf, then they will turn into a wolf.