The adze is a vampiric creature from Ewe folklore in Togo and Ghana. It is described as taking the form of an immortal firefly, However, when captured it transforms into a humanoid form where it has the power to possess humans. 
People who get possessed by the adze are seen as witches and the influence of a witch would negatively affect the people surrounding them. Many different situations would make people suspect you for being possessed by an adze such as if you are old and you younger relatives die before you or if you are poor and envy the rich. 
The adze would hunt at night, flying through keyholes, cracks, and under doors in their firefly form.  When inside they would suck the blood from sleeping people making them fall sick and die. This has been likened to mosquitos and malaria and it is thought that this folktale might stem from this danger. 
While you may not be able to fight the adze in firefly form there are some beliefs that you can force it out of a possessed victim. It will then take the form of a quasi-human, hunchbacked creature with jet-black skin and talons. When in this form you can kill it. This is supposedly very dangerous and difficult as the adze is very agile in this form. 
During the later Christian invasion, prayer was thought to guard against the adze and exorcisms were performed to expel it. 
As a vampiric creature the Adze share traits with many similar creatures such as of course Vampires.
: Bunson, Matthew (1993). The Vampire Encyclopedia. London: Thames & Hudson Ltd. p. 2. ISBN 0-500-27748-6.
: Gross, Emma; Starer (26 October 2020). "In West Africa, the Adze Is an Insectoid Source of Misfortune". Atlas Obscura. Retrieved 5 March 2022. ... the adze, it is said, slips through keyholes, under windows, around doors....