Mahadi ko Mehdi ('mai shiryarwa') shine almasihu ko mai ceto na Islama. Ance shi da Annabi Isa zasu canza duniya ta zamo kyakkyawa, zasu kawo Allah a cikin dukkan zukata, kafin Yaum al-Qiyamah ( Ranar Tashin Ƙiyama ). Musamman, shugaban katbilun Sudan Muhammed Ahmed ya yi shelar kansa a matsayin Mahadi, wanda Allah ya zaɓa don yantar da ƙasarsa. Ya ci nasarar sojojin Khedive na Misira da na Burtaniya, kawai ya mutu ba zato ba tsammani bayan watanni shida.