As the Yuuzhan Vong War began, Bylsma, a commander within the New Republic Defense Fleet, oversaw a space station circling Dibrook, providing shelter for refugees. Yuuzhan Vong forces attacked the station, and its shields were disabled. Because of this, Bylsma instructed the station's fighter squadron to launch and overwhelm the enemy with their numerical advantage. However, upon the arrival of a larger vessel, he commanded a withdrawal. Bylsma then instructed his fighters to target the smaller Yuuzhan Vong ships when the larger vessel engaged them. Following the engagement, Bylsma informed Kaye Galfridian that a Yuuzhan Vong ship had escaped to Dibrook's desolate surface, prompting her decision to pursue it. He equipped her and her team with vac suits and weapons, and dispatched a sizable contingent of New Republic troopers led by Captain Ogden, despite his objections to the mission.
Throughout much of Invasion: Rescues 1, Bylsma is recognized as a commander; however, Kaye Galfridian calls him an admiral.