Ghoul

According to Middle Eastern mythology, ghouls also known as gholes, goules, ghilan (Arabic:غيلان, singular ghul غول), Ghuls, Namnams, and Namanim (Arabic: نمانم, singular Nanam نمنم) are evil spirits of the desert.

Able to assume the shape of an animal, ghouls are grave robbers living off the flesh of the dead.

Travelers planning to cross any of the vast deserts or savannas of North Africa, the Middle East, or Central Asia should be aware that ghouls often entice men off the road and confuse them. Once the men are disoriented, the ghouls proceed to feast on their flesh.

Europe
A ghoul is a cannibalistic monsters, often thought of as undead in European folklore. They were once human, but they brought the curse on themselves by eating human flesh (dead or alive). They feed on corpses or living flesh, often abducting young children or luring away unwary people into abandoned places.

They are disgustingly ugly and stink of death. They are immensely strong, but geniuses in a sarcastic way, thus tricking them is always a better way than fighting them.

According to the tradition church bells scare away the storm, the plague, the demons, the ghouls and every hostile creature (other than humans).

By extension, the word ghoul is also used derogatorily to refer to a person who delights in the macabre, or whose profession is linked directly to death, such as a gravedigger.

In Greek mytholgy ghouls are undead cacodemons called Phasma Philinnion

Arabic folklore
In Arabic folklore a ghul is a terrible, shape shifting monsters. It may appear in the form of a hyena or a hound, opening up graves and devouring corpses. They do not hesitate to eat lonely travellers, who lost their way.

They also hunt for young children, drink blood and steal unattended coins.

In Arabic, the term is sometimes used to describe a greedy or gluttonous individual.

In Islam
Ghouls rare to mentioned in Islam, they never mentioned in the Quran but they mentioned in Hadith but not with same meaning in Arabian folklore or pre-Islamic Arabian religion it is for the misdirector people or a kind of primates, but even though when they adopted in Islamic folklore they sometimes considered as devilish class of jinn belived to be sired by Iblis.