Hurmala

In Islamic history, Hurmala Ibn Kahil Al Asadi Alkoofi was the killer of Ali al-Asghar ibn Husayn, the great-grandchild of Muhammad, on 10 October, 61 AH (680 CE).
When Imam Al-Husayn had lost all hope in the enemy in the Battle of Karbala, he came out riding on a horse and asked for water for his six-month-old child who was dying of thirst. Hurmala sent a three-headed arrow flying into the little child's throat.
He was later captured and killed by the forces of Mukhtar al-Thaqafi.