Umbra

Umbras (アンブラ), mostly known as Shadows, are non-human entities. They exist because of the human fear and anxiety. In the modern era, where the "fears" are easily spread thanks to the technology, it's easier for an Umbra to be created at any moment.

History
Until today, it is only known that they exist since fear has existed, which means they have always existed.

Known Umbras

 * Vampires (吸血鬼) ​​​​​​are umbras able to use several abilities related to the ones of a bat. They were inspired in Bram Stocker's vampire book, Dracula.
 * Werewolves (狼男), also called Lycanthropes, are umbras able to shapeshift body parts into those of a wolf and, by this mean, be able to use their abilities.