Shifters are humans who are able to turn into any animal on earth, as long as they have laid eyes on the animal. The animal forms that they take on are virtually indistinguishable from their natural counterparts. They take on the animals' abilities, strengths, and weaknesses. The difference between shifters who turn into wolves and werewolves is that shifters retain their human emotions, unlike weres, who take on the traits of their wolf forms. As humans, shifters look like any other person. Other supernatural creatures can be able to tell who and what they are using their own senses, and shifters can sense vampires and witches.
There are no set in stone personalities that must be played with a shifter. Some generalizations and commonalities, however, might be that they are much less animalistic than weres. They are less reactive and retain their human personalities. As diverse character-wise humans can be, so can shifters.
Because shifters are rarer than weres, they rarely congregate together and form groups. However, if there is more than one shifter in a family, naturally the family will likely stick together and protect one another. Shifters are much more secretive than any other supernatural species.
There is no known origin of shifters. Many think they are created by magic because they are not part animal, like weres. Additionally, they smell (to other supernatural species) more like witches, but earthier, rather than say, a wet dog.
The Shifter gene is capable of skipping generations at a time.