Islamic Sect is a term used to describe the two main branches of Islam, Shia and Sunni. Shia is the smaller of the two sects, comprising about 10-15% of the world's Muslim population. Shia Muslims believe that Ali, the son-in-law of the Prophet Muhammad, was the rightful successor to the Prophet's leadership. Sunni Muslims, on the other hand, believe that the Prophet's successors should be chosen by consensus. Shias are the followers of Ali and his descendants, while Sunnis are the followers of the Prophet Muhammad's teachings.