Ubaid Allah and his father Ziyad both were illegitimate by birth having been born out of sin. Muawiya accepted Ziyad as his brother. Ubaid Allah’s mother was Marjana hence he was called “Ibne Marjana”. Both Ubaid Allah and Ziyad were brutal and merciless murderers. Hence Muawiya and Yazid utilized their brutal skills to consolidate their rule.
Ubaid Allah was the governor of Basra and later given the charge of Kufa as well. The Kufans had already paid allegiance to Imam Husayn (a.s.) at the Hazrat Muslim bin Aqil’s hands. The crafty Ubaid Allah entered Kufa in disguise and the Kufans were deceived but as soon as he reached the Governor House, he showed his true colors of brutality and bribe. He threatened the Kufans with dire consequences if they did not pay allegiance to Yazid. He started search for Hazrat Muslim bin Aqil and sent a spy as a Shia to deliver money to him. Although Hazrat Muslim bin Aqil fought bravely with hundreds of troops but attained martyrdom. He showed the brutality and asked the troops to throw his body from the top of a building.
He promised the governorship of Rye to Umar ibn Sa’ad but later conditioned it to first fighting with Imam Huasyn (a.s.). Later, he sent Shimr ZilJaushan (l.a.) as a stand by, if Umar ibn Sa’ad refuses to fight then Shimr was to be given the charge of the army. On Ubaid Allah’s orders, the camps were removed from near the river and the supply of water was stopped from Muharram 7. Ibne Marjana is completely responsible for the massacre of the Noble Messenger (s.a.w.a.s.)’s family at Karbala and ordered to imprison the sacred family and sent to Kufa on camels without seats.
When the daughters of the Noble Messenger (s.a.w.a.s.) were brought to Ubaid Allah, he said, “Allah be praised for He disgraced and executed your family and displayed that what you said was nothing but a lie.”
Sayyida Zaynab (s.a.) said, “Allah be praised for He blessed our family with His Prophet, who was of our family and Purified us. No one would be disgraced but those who are transgressors and would not lie but a wicked person, which is others rather than us. Ubaid Allah said, “Did you see how Allah dealt with your family?”Sayyidah Zaynab (s.a.) replied, “I saw nothing but beauty! Allah ordained them to be killed and they obeyed and hurried after their tombs, and soon Allah will gather you and them (on the Day of Judgment), and they will complain of you to Allah. Now look forward to seeing who wins the claim. May your mother mourn your death, O son of Marjana.”
After the death of Yazid, Ubaid Allah fled to Syria. Amir Mukhtar Saqafi rose against the Umayyads and their faithful Ubaid Allah was sent to fight Amir Mukhtar’s heroic bands who wanted to avenge Imam Husayn (a.s.) brutal massacre. Amir Mukhtar sent a strong contingent of 12,000 soldiers to Mosul under the command of Ibrahim bin Malik Ashtar. He saw some of the assassins of Imam Husayn (a.s.) like; Shees bin Rabiee, Shimr Ziljaushan, Umar ibn Sa’ad. He allowed them to go to Kufa and once in a house, they were planning to attack Amir Mukhtar’s forces, they along with others were arrested and killed and some of them were made captive. Again, Ibrahim bin Malik Ashtar went in search of accursed Ubaid Allah. Both the armies faced each other but soon Umayyads made a bid to escape. But Ibrahim encouraged his soldiers saying, “O partisans of truth and helpers of religion, kill these children of Shaitan.” Then attacking accursed Ubaid Allah, he said, “He is the same who restricted water to Imam Husayn and misbehaved with family of prophet hood and Imamate, made them captive and dragged in the streets of Kufa and Syria.” His words had the desired effect and his forces devastated the Umayyads. Ibrahim killed Ubaid Allah himself and sent his head to Amir Mukhtar.
It is also reported that a drop of blood from the sacred severed head of Imam Husayn (a.s.) was fallen on the accursed Ubaid Allah’s thigh and penetrated through his body. The wound was never healed and continued to smell very bad and to cover-up for the unpleasant smell of the wound, he always wore musk. This was worldly curse for him!
Sources used: WIKIPEDIA, The Fate of the Killers of Imam Hussain -Ahle Sunnat (ahle- jannat.WordPress)
Al-Murtaza.com, Revolvy.com, WikiShia.net