Buer is a spirit that appears in the 16th century grimoire Pseudomonarchia Daemonum and its derivatives, where he is described as a Great President of Hell, having fifty legions of demons under his command. He appears when the Sun is in Sagittarius. Buer teaches Natural and Moral Philosophy, Logic, and the virtues of all herbs and plants. He also heals all infirmities, especially of men, and gives good familiars.
He has been described as being in the shape of Sagittarius, which is as a centaur with a bow and arrows. Additionally, Louis Breton created an illustration of Buer, later engraved by M. Jarrault, depicting the demon as having the head of a lion and five goat legs surrounding his body to walk in every direction. This illustration has been featured on several albums including Morbid Angel's Blessed are the Sick LP, Coil's 'Wrong Eye / Scope' single, Cloven Hoof's 2008 album The Definitive Part One, and a 1981 Black Sabbath bootleg LP entitled Buer Album.
Although the etymology of his name is uncertain, curiously there was an ancient city named "Buer" (now Gelsenkirchen) in Westphalia, Germany.
Buer is also used as a surname.