Arc-Royal Defense Cordon
When Katherine Steiner-Davion claimed independence for the Lyran half of the Federated Commonwealth, several of her most prominent detractors began to move against her. One of those detractors was the Duke of Arc-Royal, and de facto leader of Heimdall, Morgan Kell. In response to Katherine's power grab, Morgan declared himself Grand Duke of sixteen Lyran worlds along the Clan Jade Falcon border, ostensibly to ensure their defense against the powerful Clan. Officially, Katherine thanked Kell for taking charge of the defense for the worlds and made it seem as if he had done so with her consent, but, behind the scenes, she began plotting to destroy the ARDC and remove Morgan Kell as a threat to her realm.
In order to pin Kell and his troops down, Katherine removed all units loyal to her from those worlds. Kell responded by maneuvering nearby House units and mercenaries into the ARDC that were loyal to Archon-Prince Victor. Mercenary units like the Kell Hounds and Blue Star Irregulars, FedCom units loyal to Victor, and Clan Wolf-in-Exile formed the bulwark against Clan Jade Falcon. Kell's precaution against the Falcons proved justified when the Jade Falcons launched their invasion in 3058 that reached as far as Coventry, though they came at an angle that bypassed the ARDC.
When the FedCom Civil War broke out in 3062, Victor instructed Morgan to keep the ARDC units there as a brake on the Falcons, a move that proved fortuitous when they invaded again in 3064. After the Blair Atholl Agreement ended the Falcon Incursion, Kell helped place Victor's younger brother Peter on the throne. After Katherine had surrendered and the Estates General ratified Peter as Archon, Morgan folded the ARDC back into the Lyran Alliance, though Arc-Royal became the capital of Donegal's military theatre, as Pandora had been captured by the Falcons during their invasion.
The Defense Cordon's military initially consisted of locally-raised militia units and mercenaries attracted by good contracts. However, after the split in leadership of Clan Wolf, the Cordon became the home for Clan Wolf-in-Exile (largely due to the leader of the Wolves being Morgan's son, Phelan Kell). These Wolves were never fully integrated into the Cordon's military structure, but still served the Cordon against the Jade Falcons during the second invasion.