shadow commander. a powerful military mind, rarely seen but certainly heard. but as isis continues its slaughter in iraq attempting to edge closer to baghdad, this man is emerging from behind the scenes the head of iran's elite qods force. a man the u.s. links to attacks on its own troops in the past may prove critical in the battle for tikrit. >> he's a legend. he was a player in the iran-iraq war. he has a whole lot of experience in combat not only in that war, but also in conflicts in the interim, but also against the united states. >> reporter: he is credited with the fall of isis in a key iraqi town and he's battled islamic state militants in syria and now is set on retaking tikrit the hometown of former dictator saddam hussein. iranian reports suggest he was