The King of the South will become, strong, but one of his commanders will become even stronger than he and will rule his own kingdom with great power.

Saddam is the commander whose power will be greater than that of Iran (Persia). 

George Bush Snr, the president of the most powerful nation in the world, was unable to get rid of Saddam Hussein, even though he inflicted a defeat on his army in Kuwait. In the longer term Saddam was the victor.

When warning his people to prepare for that war Saddam said, "Let everybody understand that this battle is going to become the mother and father of all battles."  This was a prophetic.  His machinations will eventually begin the series of battles between the King North and the King of the South and the Man of Intrigue described in Daniel 11,12.