Invisibility in the context of "Strigoi"

In classical mythology, the Cap of Invisibility (Ἅϊδος κυνέη (H)aïdos kyneē in Greek, lit. dog-skin of Hades) is a helmet or cap that can turn the wearer invisible, also known as the Cap of Hades or Helm of Hades. Wearers of the cap in Greek myths include Athena, the goddess of wisdom, the messenger god Hermes, and the hero Perseus. Those wearing the Cap become invisible to other supernatural entities, akin to a cloud of mist sometimes used to remain undetectable.

Herbert George Wells (21 September 1866 – 13 August 1946) was an English writer, prolific in many genres. He wrote more than forty novels and dozens of short stories. His non-fiction output included works of social commentary, politics, history, popular science, satire, biography, and autobiography. Wells is most known today for his groundbreaking science fiction novels; he has sometimes been called the "father of science fiction", a title that has also been given to Jules Verne and Hugo Gernsback.

In addition to his fame as a writer, he was prominent in his lifetime as a forward-looking, even prophetic social critic who devoted his literary talents to the development of a progressive vision on a global scale. As a futurist, he wrote a number of utopian works and foresaw the advent of aircraft, tanks, space travel, nuclear weapons, satellite television and something resembling the World Wide Web. His science fiction imagined time travel, alien invasion, invisibility, and biological engineering before these subjects were common in the genre. Brian Aldiss referred to Wells as the "Shakespeare of science fiction", while Charles Fort called him a "wild talent".

The One Ring, also called the Ruling Ring and Isildur's Bane, is a central plot element in J. R. R. Tolkien's The Lord of the Rings (1954–55). It first appeared in the earlier story The Hobbit (1937) as a magic ring that grants the wearer invisibility. Tolkien changed it into a malevolent Ring of Power and re-wrote parts of The Hobbit to fit in with the expanded narrative. The Lord of the Rings describes the hobbit Frodo Baggins's quest to destroy the Ring and save Middle-earth.

Scholars have compared the story with the ring-based plot of Richard Wagner's opera cycle Der Ring des Nibelungen; Tolkien denied any connection, but scholars state that at the least, both men certainly drew on the same mythology. Another source is Tolkien's analysis of Nodens, an obscure pagan god with a temple at Lydney Park, where he studied the Latin inscriptions, one containing a curse on the thief of a ring.

A magic ring is a mythical, folkloric or fictional piece of jewelry, usually a finger ring, that is purported to have supernatural properties or powers. It appears frequently in fantasy and fairy tales. Magic rings are found in the folklore of every country where rings are worn. Some magic rings can endow the wearer with a variety of abilities including invisibility and immortality. Others can grant wishes or spells such as neverending love and happiness. Sometimes, magic rings can be cursed, as in the mythical ring that was recovered by Sigurð from the hoard of the worm Fáfnir in Norse mythology or the fictional ring that features in The Lord of the Rings. More often, however, they are featured as forces for good, or as a neutral tool whose ethical status in the narrative derives from the character that uses it.

A finger ring is a convenient choice for a magic item: It is ornamental, distinctive and often unique, a commonly worn item, of a shape that is often endowed with mystical properties (circular), can carry an enchanted stone, and is usually worn on a finger, which can be easily pointed at a target.