Possible Clues:

• Many Iranians' Islamic sect
• Like most Iranians
• Like the majority of Iraqis and Bahrainis
• Titan from Tahitian's Islamic branch
• Most Azerbaijani
• Branch of Islam associated with Iran
• One observing the holiday of Arba'een
• Sect that doesn't have a Sunni disposition?
• Twelvers' Islamic branch
• Islam's second-largest branch