The Gilead Guards are the police force of the city of Gilead. They are seen throughout The Fall of Gilead comic serving the Gunslinger's and helping where needed. They are also seen to man the entrance gate to Gilead.
Though it seems resonable that most of them were followers of The White as we see three of them attempt to arrest Marten Broadcloak which they pay for by being turned into dogs, it seems that John Farson or the Crimson King managed to convert some to their side. They are also seen not allowing Sheemie into the city when Steven Deschain orders the city gates to be closed.
Additionally they inform the Gunslingers of Marten fleeing Gilead with Farson, also telling them the Kingson's body is missing from the morgue.
Due to this some of their members are responsible for the deaths of Abel Vannay, Christopher Johns, Steven Deschain as well as the entire population of Gilead by burning them alive with flame-throwers during the fall of the city.