The Mahdi, Abdullahi, and the Dervishes The Mahdi, Abdullahi, and the Dervishes, who were the followers of the Mahdi, were a formidable force. They were a religious and political movement that emerged in Sudan in the late 19th century. The Mahdi, Muhammad Ahmad, declared himself the Mahdi, the prophesied redeemer of Islam, and led a revolt against the Egyptian and British rule in Sudan. Abdullahi, his successor, continued the struggle, and together they established a powerful state that challenged the colonial powers.