The Fourth Capellan Chargers were one of the regiments taken to Calloway VI in March 2789 in an attempt by Chancellor Barbara Liao to strike a decisive counterblow against the Free Worlds League, which had been prosecuting a hugely successful campaign against the Confederation. Following on the heels of the massacre conducted on New Delos in 2788, the strike at Calloway VI was intended to break the League's morale and willingness to fight. The task force assembled to assault Calloway IV, dubbed Task Force Devlin, consisted of thirty WarShips, fifty attack DropShips, fifty-six transport DropShips, numerous transport JumpShips and seven regiments of 'Mech forces. The 'Mech forces included the Red Lancers, which the Chancellor had dictated she would be leading in the field, as well as the Ares Titans, another elite formation - and which ensured that both of Barbara's sons, Major Barnabus Liao and Baltazar Liao, were on the front lines. In addition to the Red Lancers and the Ares Titans the CCAF deployed the First and Second Sian Dragoons, the Fourth Capellan Chargers, the Third Confederation Reserve Cavalry and the Fifth Liao Lancers. The overall command of the Task Force fell to Colonel Jacen Devlin aboard his flagship, the Du Shi Wang-class battleship CCS Sundermann Liao.
Unfortunately for the Capellans, the battle for Calloway was a disaster. Unlike the earlier action at New Delos, the Maskirovka didn't have cracked Free Worlds League codes to supply to the CCAF, so the Task Force was going in blind; the Task Force had also been betrayed by a traitor within the naval fleet, who had been sickened by the massacre on New Delos and who passed word of the impending attack to League agents at Propus while the task force was being assembled. Also working against the fleet was the presence of Barbara Liao - who was able to order the Task Force to continue the attack against the advice of her subcommanders when things began going wrong, and whose very presence sapped resources away from the main Task Force because of the need to keep her safe... something that began almost immediately.
When the Task Force jumped into the Calloway system, it found the First Oriente Provincial Squadron waiting for it at the zenith jump point, while waiting on Calloway VI were four provincial regiments - the First Fusiliers of Oriente, the Third and Eighth Oriente Hussars and the Helm Cuirassiers - complete with an attached group of attack DropShips and a number of wings of aerospace fighters. The First Oriente Provincial Squadron didn't waste any time attacking, but despite being outnumbered, deliberately did everything they could to target transport ships, rather than escorts. By the time the four Atreus-class battleships and the four League II-class destroyers had been destroyed, Task Force Devlin had lost a quarter of its transport JumpShips and more than a regiment each of aerospace fighters and 'Mechs. Wounded in the engagement was Barnabus Liao, whose Overlord-class DropShip had been crippled in the battle.
Barbara Liao insisted on the attack going ahead, with Task Force Devlin burning towards Calloway VI - a two-week journey - unaware that the Free Worlds League Navy Third Fleet was waiting in two large groups at Holt and Oriente, and had been made aware of the attack. Twelve hours out from the surface of Calloway VI League assault craft and fighter carrier DropShips were waiting, and swarms of League aerospace fighters threw themselves at the lighter Capellan fighters. The resulting battle lasted two days, and by the time Task Force Devlin had managed to secure orbital supremacy above the planet the Task Force had lost seven more transport DropShips and two regiments of aerospace fighters.
The Capellan landings went ahead, with the Task Force mustering roughly five regiments of 'Mechs - a number almost equaled by the defenders, who had spent two weeks fortifying positions, creating redoubts and evacuating civilians from the major cities on the planet. For ten days the Capellan ground forces fought a war of attrition against the defenders, hampered by the need to protect the Chancellor; when Barbara Liao finally announced a withdrawal from the planet only a third of the Red Lancers remained to evacuate her, and Barnabus Liao was killed along with the other members of the Ares Titans while attempting to fall back. Even as the Capellan forces evacuated from Calloway VI, they learned that their transport JumpShips had been destroyed. The FWLN Third Fleet had jumped to Calloway a week into Task Force Devlin's two-week approach to the planet; arriving close enough to the transport JumpShips to engage immediately, the Third Fleet had destroyed all bar two of the JumpShips, along with their small WarShip escort, and were burning towards Calloway VI, determined to avenge New Delos.
Colonel Devlin assigned six WarShips to evacuate Barbara Liao, while his remaining forces acted as a rearguard against the vengeful League forces. By the time the Chancellor's ships were away, Devlin was dead, and the Sundermann Liao had been destroyed, along with the bulk of Task Force Devlin. Of the original Task Force Devlin ships and forces, the survivors who managed to escape mustered just twelve WarShips, six attack DropShips, five 'Mech transports and three fighter carriers, transporting away the remnants of the ground forces - of which only the Red Lancers, Third Confederation Reserve Cavalry and Fifth Liao Lancers had managed to survive in any numbers. Lost during the naval battle was Baltazar Liao, aboard the Essex-class destroyer CCS Calseraigne, destroyed by the Aegis-class heavy cruiser FWLS Pleiades.
- First Succession War, pp. 58–60: "Debacle at Calloway"