[1] The name Dhammiyya was derived from the Arabic word Dhamm, meaning blame.
[1] The sect was also known as the 'Ulyaniyya or 'Alya'iyya, named after ‘Ulyan (or 'Alya) ibn Dhira' as-Sadusi (or ad-Dawsi, or al-Asdi), and appear to have been active around 800 CE.
[2][3] The Dhammiyya Shia believed that Ali was God and Muhammad was his appointed Prophet.
[1] They believed that while Muhammad was the appointed Prophet of Ali and acknowledged him to be God, he called for the worship of Allah and deceived people into thinking that Allah was God instead of Ali.
[1] They believed that Muhammad was sinful for doing so, and worthy of blame- from which the Dhammiyya get their name.