- Gaius van Baelsar ("The Black Wolf" and Legatus Legionis, defected)
- Nero tol Scaeva (Tribunus Laticlavius, defected)
- Livia sas Junius ("The Witch of Dalmasca" and Tribunus Angusticlavius, deceased)
- Rhitahtyn sas Arvina (Praefectus Castrorum, deceased)
- Aulus rem Vulso (Pilus Prior of the 3rd Cohort, deceased)
- The Indolent Imperial
- Fordola rem Lupis ("The Butcher" and Pilus Prior of the Cania Lupi, taken to the XIIth Imperial Legion, conscripted by the Ala Mhigan Resistance)
- Grynewaht pyr Arvina (Decurio, taken to the XIIth Legion, deceased)
After successfully capturing Ala Mhigo, the XIVth Legion was poised to annex the rest of Eorzea. As next part of their invasion plan, the legion attempted to capture Mor Dhona due to Lake Silvertear believed to be a nexus of aetherial energy (and therefore a risk of fueling the summoning of primals in defense of the realm). What Garlean scholars failed to take into consideration was the legends surrounding its guardian: as the fleet moved into Mor Dhona airspace, the Father of Dragons Midgardsormr emerged from the lake. After centuries of absence, the king of kings called forth the Dravanian Horde with song to repel the Garlean fleet. Even the mighty Agrius super-dreadnaught could not withstand the terrible power of Midgardsormr's energy blasts, and it fell into the lake with the great wyrmking coiled around it. The ceruleum fuel tanks suddenly ignited, killing Midgardsormr and destroying a seal on the flow of aether at the lake, creating a blinding pillar of light.
With the loss of the Agrius, Gaius was forced to withdraw the surviving fleet to Ala Mhigo. Worse yet, the breaking of the seal ensured the native beast-tribes would have an abundant supply of aether to summon their primals in response to both the invasion and disputes with the city-states. For ten years, the invasion of Eorzea was put on hold, beginning the Age of Calm.
Emperor Solus zos Gavus, seeing the crisis in Eorzea, approved of Nael van Darnus's more extreme plan: Project Meteor. In response to the implications of this threat, the city-states reinstated the Eorzean Alliance and recreated the Grand Companies. Gaius and his Legion were ordered to aid van Darnus with his plan. However, the Legatus did not approve of his peer's apocalyptic plans, and secretly aided the Eorzean Alliance in their efforts to thwart the White Raven.
A Realm RebornEdit
Although the Emperor Solus zos Galvus abandoned any plans for Eorzea after Project Meteor was less than successful, Gaius van Baelsar would not give up his ambition to bring Eorzea under his control. With the aid of a spy planted in the Grand Companies by High Legatus Varis yae Galvus, the XIVth Legion quietly set up several outposts in Eorzea in the years after the Calamity.
In addition to reusing Nael van Darnus's old fortress Castrum Novum (now called Castrum Centri), the Legion set up a major stronghold at Northern Thanalan, as well as additional bases in La Noscea, the Black Shroud, and Coerthas. They also performed research expeditions into the Binding Coil of Bahamut at Castrum Occidens, as well as a Provisional Research Camp in the wreckage of the Agrius.
Using the ancient anti-primal weapon unearthed at Ala Mhigo, the Ultima Weapon, Gaius hoped to subjugate the city-states and beast-tribes. Though the beast-tribes backed down, the Eorzean Alliance responded to his ultimatum with Operation Archon: shutting down his supply lines and besieging Castrum Meridianum. The Ultima Weapon was destroyed by a team of adventurers, and Gaius himself seemingly perished as the inner Praetorium collapsed from the damage caused by Ultima.
Since the apparent fall of the Black Wolf, the XIVth Legion remained dormant within the bases, and their most senior known surviving officer, Nero tol Scaeva, later disappeared in a Voidgate at the Syrcus Tower and re-emerged to defect to Garlond Ironworks. After Varis zos Galvus rises as emperor of Garlemald, the remnants of the XIVth Legion was absorbed into the forces of the succeeding XIIth. Gaius later reveals himself to have survived the Praetorium's destruction and lives on as the Ascian-hunting mercenary Shadowhunter.
"Steel Reason" plays in all the battles against the tribunes of the XIVth Imperial Legion, except for Gaius who has his own battle theme, "Bite of the Black Wolf".