I haven’t come across that....i’v read it will be blk ppl from habasha (Ethiopia), the muslims of Arabia at that time will be in such a weakened state (some muhaddith have said a weak state in terms of imaan and some say weak militarily) and this will happen after a Great War....and I can envisage that when WW3 happens (nuclear bombs and destruction) there will be total disarray everywhere and social order itself will break down and then we will have warlords like we had/have in Afghanistan and the Middle East.
The Sufyani will also emerge from the depths of Damascus and he will kill like no other....he will have a 3 pronged whip / lance that will kill whoever it strikes. And then he will spread his fitna far and will kill the ahle bayt in Kufa and then the black banners will come from Khorasan to challenge his army and will defeat them ....
TBC