Aiwel (Aiwel Longar or Longar) is the founder of the hereditary priesthood known as the Spear Masters by the Dinka people of the southern Sudan swamplands. Aiwel’s mother reputed conceived him by allowing the waters of the Nile to enter her after her husband had died. He is considered a trickster god and first born of the creator. From early childhood, Aiwel possessed the abilities of a Spear master, that is, to make his word come true no matter the consequences. After the death of his mother, Aiwel returned to the river, but later he returned as an ox, Longar, to lead his people to a promised land during a time of drought.
The Spear-Masters continue to guide the Dinka people in modern times. They are responsible for spearing to death the sacrificial oxen. They answer everyday questions like 'who stole my bow and arrow?' and 'when will it rain?' by presiding over sacrifice and trance. A volunteer will enter into a trance, usually through use of some intoxicating substance, and becomes possessed by one of the god-spirits. The resultant wild movements are interpreted by the Spear-Master and relayed to the gathered crowd. Life for the Spear-Master comes to an end, when he imparts final advice to his people before voluntarily being buried alive.