He is Ammar bin Abi Salamah bin Abdullah bin Arar bin Roa'as bin Dalan bin Sabeqah bin Nashij bin Dafi'I bin Malik bin Jasham bin Hashid bin Jasham bin Khairan bin Nawf bin Hamdan bin Malik bin Zaid al-Hamadani al-Dalani.
It was narrated by Ibn Hajar as saying, "Ammar bin Abi Salama Dalan al-Hamdani, has participated in every battle alongside Imam Ali bin Abi Talib (A. S), and was killed with Imam Al-Hussein bin Ali (A. S) in the battle of Karbala.
Sheikh Al-Amini mentioned him as one of those who fought under the leadership of Imam Ali (A. S) in Siffen battle, and also considered him among the companions of Imam Al-Hussein (A. S) in the battle of Karbala.
Abu Jaafar al-Tabari narrated that, "He was one of the companions of Imam Ali (A. S) and one of the Mujahideen under his leadership in the three wars he fought, as he once asked the Commander of the Faithful (A. S) when he headed from Dhi Qar to Basra, saying (O, my lord, what would you do if you faced them?,) so the Imam replied, (I would call them to obey Allah Almighty, yet if they refused, I would fight them,) then Abu Salameh said (So, they will never defeat the caller for Allah.)"
One of the narrations by Al-Sarawi mentioned that al-Dalani was killed in the first engagement between Imam Al-Hussein's companion and the army of Yazid, as a number of the most prominent companions were killed. He also was mentioned in Ziyara supplication as, "Assalam ala Ammar bin Abi Salama Al-Hamdani."
Source:
Mawsueat Karbala Al-Hadharia "Karbala Civilizational Encyclopedia", publication of Karbala Center for Studies and Research.
[Vol. 6, p. 34-35].