BAGHDAD - Abu Deraa sits at home in Baghdad's Sadr City, ringed by images of 7th century Shi'ite Muslim Imams Ali and Hussein. A hero to Shi'ite militiamen during Iraq's civil war, he no longer fights but still stirs the hearts of men now battling Islamic State.Nearly a decade after Iraq's worst sectarian bloodletting, the country faces a new period of darkness: Sunni jihadists have captured swathes of territory in the north and west, and efforts to roll back those gains have exacerbated tensions between Sunni and Shi'ite communities.Abu Deraa, whose nom de guerre means father of the shield, is defiantly proud of his past, which includes brutal raids on Sunni areas whose residents still tremble at his name. He now sees himself as an anchor in a new war against evil forces.On any given day, young men flock to his house to pay tribute and acolytes join the fight against Islamic State under the banner of various armed factions."How would you feel if your family was slaughtered? How would you act and where would you go? Those who have killed and committed crimes should be punished," Abu Deraa told Reuters in an interview."If you aren't capable of doing it yourself, we are here for you. We will give you back your rights."Islamic State insurgents have killed thousands of Iraqis and displaced many more in recent months. They often booby trap areas under their control before leaving, complicating return.