Soleimani, widely considered as the second most powerful military leader in Iran, had led the fight against ISIS from the front line.
According to a CNN analysis made by Nick Paton Walsh, ISIS was seen as a threat to Shiite Iran, which was aware of the "leverage" it would have in helping Iraq defeat them.
Seen by the US as a "key adversary involved in plotting attacks against their allies and assets," it is important to remember the role both he and Iran had played in the fight against ISIS.
An NBC news report back in 2015 said Soleimani had helped drive out ISIS forces from Tikrit, Saddam Hossain's hometown, helping to build Iran's image of bringing stability to the region without any discernable western assistance.
Middle East analyst for the Heritage Foundation Jim Phillips said, "He's probably the most powerful figure that is generally unknown outside Iran and the Middle East. He's essentially Iran's viceroy for Iraq."
He added, "He's the puppet master controlling numerous Iranian surrogates in various countries."
Political pundits and analyists saw Soleimani as among the most influential figures in the Middle East of the past decade, whether seen from the heroic lenses of post-revolutionary Iran or from the eyes of a western adversary.
The consequences of his death will be seen affecting the region for the next several years, said the CNN analyst.