In traditional demonological

Demonology

Demonology is the systematic study of demons or beliefs about demons. It is the branch of theology relating to superhuman beings who are not gods. It deals both with benevolent beings that have no circle of worshippers or so limited a circle as to be below the rank of gods, and with malevolent...

 discourse, Great Duke (Also Grand Duke

Grand Duke

The title grand duke is used in Western Europe and particularly in Germanic countries for provincial sovereigns. Grand duke is of a protocolary rank below a king but higher than a sovereign duke. Grand duke is also the usual and established translation of grand prince in languages which do not...

or simply Duke

Duke

A duke or duchess is a member of the nobility, historically of highest rank below the monarch, and historically controlling a duchy...

) is a rank, denoting a position of prominence amongst the hierarchy of demons. The title of Great Duke reflects the inclination of early Christian

Christian

A Christian is a person who adheres to Christianity, an Abrahamic, monotheistic religion based on the life and teachings of Jesus of Nazareth as recorded in the Canonical gospels and the letters of the New Testament...

 demonologists to categorize the denizens of Hell

Hell

In many religious traditions, a hell is a place of suffering and punishment in the afterlife. Religions with a linear divine history often depict hells as endless. Religions with a cyclic history often depict a hell as an intermediary period between incarnations...

 into hierarchical systems akin to those of the Monarchies of Europe, and mirroring the angelic hierarchy.