The Adze is a vampiric being from Ewe folklore in Togo and Ghana. It normally looks like a firefly, but it will transform into human shape when captured.
In its human form, the Adze has the power to possess ordinary humans and turn them into witches.
A person is suspected of being possessed in a variety of situations, including: women with brothers (especially if their brother’s children fared better than their own), old people (if the young suddenly started dying and the old stayed alive) and the poor (if they envied the rich).
The Adze’s effects are generally felt by the possessed victim’s family or those the victim is jealous of. In firefly form, the Adze can pass through closed doors at night and suck blood from people as they sleep. Victims would fall ill and die.
Tales of the creature and its effects were probably used to describe the potentially deadly effects of mosquitos and malaria. There is no defense against an Adze.
Source: Bunson, Matthew (1993). The Vampire Encyclopedia.