The Shia branch of Islam is one of the two main sects of Islam, the other being Sunni Islam. Shia Muslims believe that leadership should have remained within the family of the Prophet Muhammad, specifically with his cousin and son-in-law, Ali. This belief leads to a distinct interpretation of Islamic teachings and practices. Shia Islam is characterized by its emphasis on the role of Imams, who are considered spiritual leaders and guides. These Imams are believed to be divinely appointed and possess special knowledge. The largest Shia group is the Twelvers, who recognize a line of twelve Imams, with the twelfth Imam, Muhammad al-Mahdi, believed to be in occultation and will return as a messianic figure.