In the folklore of Shia Islam, Shemr is a villainous figure, from the tribe of Banu Kalb who was the brother Umm ul-Banin, who is usually associated with the death of the prophet Muhammad's grandson Hussein ibn Ali at the Battle of Karbala.
Shemr is depicted in the passion plays during the Shia festival of Ashura.
Shemr was the son of Zeljoshan and was from the Khavarej tribe, he was keen on fighting with Imam Hassan against Muawiya although he was against Imam Ali. He later on got selected for Muawiya's Army after Imam Hassan abdicated his government, he fought in the battle of Kerbala and was the person who killed Imam Hussein's son Ali Asghar.
He was killed by Mukhtar ibn Sakafi as vengeance for Imam Hussein.