For 10 points, name this second largest branch of Islam after Sunni.
One branch of this religious sect is the Zaidis. Members of this sect believe in eight practices in place of the five pillars. Another of its sects believes that Muhammad al-Mahdi is the twelfth imam, is alive and hidden, and will help Jesus bring the day of judgement. That sect, this religion's largest, is the Twelvers. Its adherents believe Ali was the true successor to Muhammad. Many adherents are found in Azerbaijan and Iraq, and it is the dominant religion in Iran. For 10 points, name this second largest branch of Islam after Sunni.
One branch of this religious sect is the Zaidis. Members of this sect believe in eight practices in place of the five pillars.
{Shi'a} Islam [accept {Shi'ite}; prompt on {Islam} or {Muslim} until “{successor} to {Muhammad}”]