Aswad bin ‘Abd-e-Yaghooth was the cousin of Rasulullah (sallallahu ‘alaihi wasallam) i.e. Aswad’s father was the brother of Hazrat Aaminah, the mother of Rasulullah (sallallahu ‘alaihi wasallam). His family lineage is as follows: Aswad bin ‘Abd-e-Yaghooth bin Wahab bin Munaaf bin Zuhrah.
He was also one of the bitter enemies of Rasulullah (sallallahu ‘alaihi wasallam). When he would see the poor Muslims, he would sarcastically remark, “These are the future kings of the world who will become the heirs of Chosroe’s kingdom.” When he would see Rasulullah (sallallahu ‘alaihi wasallam), he would sarcastically say, “What is the matter? Has nothing descended from the heavens today? He would also make other similar remarks.
(Extracted from Seeratul Mustafa 1/221)