Abnormals is the term used to describe the creatures on Sanctuary. Most of them are believed to be natural mutations, although some have been created on purpose. Many Abnormals have been influential to human history, although most of the world is unaware of this fact; the ancient vampire civilization was responsible for many advances in science and technology. Important historical figures such as Nikola Tesla or U.S. president Warren G. Harding were actually Abnormals.