This means west Africa. If you google "Ashanti" and "Obeah" you'll get a lot of results.
Here's one example
http://scholar.library.miami.edu/slaves/Religion/religion.htmlThe practice of harnessing supernatural forces and spirits for one’s own personal use, known in some parts of Africa as ‘Obeye’ (an entity that lives within witches), has taken on many names in the Caribbean islands, such as Shango (Trinidad), Santeria (Cuba), Vodun or Voodoo (Haiti), Ju-Ju (Bahamas), Obeah (Jamaica),. Although African slaves usually practiced Obeah for "evil" or rather self-interested, instrumental purposes, this faith also aided them as a source of strength and clandestine resistance. The practice of Obeah is the belief that one can use certain spirits or supernatural agents to work harm to the living, or to call them off from such mischief. Generally, the British used the term Obeah to describe all slave acts and practices that were considered supernatural or evil in nature, such as rituals and fetishes.
Modern historians believe that Obeah originated from the Ashanti and Koromantin tribes of Africa on the Gold Coast, and that imported slaves introduced it to the Caribbean as early as the mid 17th century. Regardless of its use, for ‘evil’ or ‘good’, the Obeah men were treated with the utmost respect and fear by all whom met him. The Obeah man and women played a prominent role in the Caribbean slave societies from the beginning of the slave trade. They functioned as community leaders and teachers of the African folk’s cultural heritage. Many Africans believed that the Obeah man had within his power the ability to render someone invincible, resuscitate the dead, cure all diseases, protect a man from the consequences of his crimes, and cause great harm to anyone he wished. Yet the Obeah man’s most powerful gift was not his ability to steal people’s shadows , as the act of obeah or "hexing" was described, but his intricate knowledge of herbs and poisons. The term Obeah also suggested the word "poison" in the Caribbean plantations, this being the preferred and most effective tool that this practitioner of "magic" had at his disposal. Through the use of herbs and medicine, the Obeah man, was able to "miraculously" cure or poison (obeah) a person to death. Considering the development and practices (bloodletting) of "modern" European medicine at the time, an ill person had a much greater chance of survival by seeking out an Obeah man rather than a white physician.
You might be more interested in this one:
http://www.sacred-texts.com/afr/ppj/ppj001.htm ASHANTI CULTURAL INFLUENCE IN JAMAICA. I compares practices and names used in the religion in both regions.