What are cold ones?

They were supposedly vampires. All that is fact. The cold ones are vampires
The Native American tribe, the Quileutes, call the "cold ones" Apotamkin. The Apotamkins have cold skin, incredible speed and strength, are immortal, undead, drink blood, and more Supernatural powers, such as their eyes changing color.

A good example of the "cold ones" is in the book and movie "Twilight." By the way, it should be mentioned that the "cold one" is a made-up character by the author. In fact, there are no Quileute legends about "cold ones."

The author of the "Twilight" saga has stated that she made up this fictional vampire legend by herself, and only had her Quileute character tell it for the purposes of her plot. However, she did base other parts of her books on real Quileute mythology. For example, it is true that according to legend the Quileute tribe is descended from wolves who were changed into men. Even the tribal name "Quileute" comes from their Word for wolf, Kwoli.
Hopes this help! http://www.jesseneo.com/reading/the-cold-one-vampire.php