After the events of "Cry for Justice" left Star City in ruins, a mysterious forest in the shape of a star grew out of the rubble overnight. It was revealed in "Brightest Day" that the growing of the forest was the work of the recently resurrected Deadman, under the direction of his White Lantern ring.
During the Rise and Fall arc, Oliver Queen was apprehended and tried for the killing of Prometheus. The punishment he was handed down was banishment from Star City. He has since made the forest his new residence, and this is the costume he use during this current story arc.