Halverson was one of the last team leaders in Rainbow, the elite, multi-national counterterrorism force. A skilled and courageous operator, Halverson was highly regarded by her team, but her willingness to break rules in order to get the job done often put her at odds with her superior officers. When the European Federation withdrew its personnel from Rainbow, the unit was deactivated and its American operators were reassigned to units in the new Joint Strike Force. Because of her exemplary combat record, Halverson was assigned to the 15th Special Operations Battalion and given command of Delta Company. During the war, the 15th performed countless high-risk missions in Europe, including strikes on EuroFed orbital uplinks and Russian tactical nuclear stockpiles. When Scott Mitchell took control of the 15th near the end of the conflict, Halverson operated as Mitchell's Second-in-Command, and took part in dangerous missions behind enemy lines during the retreat from Paris. Under Halverson's leadership, Bravo Company has become a hardened unit of elite special forces troops, capable of defeating units much larger than their own.