|Unit Profile (as of 2582)|
|Parent Formation||Outworlds Alliance Militia|
The Santiago Carabiniers regiment was formed during the Reunification War, was the sister regiment of the Pitkin Lancers and was one of the first 5 BattleMech regiments to exist within the military command of the Outworlds Alliance.
The Santiago Carabiniers and their sister regiment, the Pitkin Lancers, were formed during the Reunification War, using BattleMechs and equipment captured from the SLDF 27th Royal Brigade on Haynesville in 2852, and was one of the first two true BattleMech regiments within the Outworlds Alliance Militia; while the 1st Alliance BattleMech Regiment (Light) formed earlier, the 1st Alliance was a provisional organization initially equipped with a mix of BattleMechs and WorkMechs.
The Carabiniers formed on Alpheratz and their first combat deployment was a combat drop onto the heavily contested world of Lushann; the Star League had tasked the entire 15th Division with destroying the Pitkin Lancers, who had been deployed earlier alongside the Alliance Borderers and the 3rd Armored Division. The Lancers had been reinforced by two regiments of the Pitcairn Legion, but the SLDF had responded by focusing the 15th on tying down the Legion and preventing them from conducting combat operations elsewhere. The combat drop executed by the Carabiniers allowed the Pitcairn Legion to disengage from the 15th, which in turn freed up both the Legion and the Carabiniers for one of the most important battles in the war.
Having received intelligence indicating that the commander of the SLDF task force, General Amos Forlough, was going to strike the mining world of Tellman IV with three brigades of SLDF forces, Outworlds Alliance Militia Chairman Welkens Nordd deployed the entire Pitcairn Legion, the Santiago Carabiniers and two regiments of infantry to the icy mining world of Tellman IV in an attempt to check Forlough's forces. Arriving in system ahead of the SLDF troops, Colonel Elias Pitcairn was able to deploy his forces in hiding, and to keep the scouting SLDF forces under covert observation from the day they arrived.
In what became known as the Day of Vengeance, Colonel Pitcairn waited until the SLDF scouts had brought the bulk of the main SLDF force onto the planet before leading a strike against the scouts and then into the SLDF landing zone; in a maelstrom of fire and vengeance, the Legion and the Carabiniers rampaged through the SLDF lines, attempting to destroy as many 'Mechs and tanks as possible while they were still unloading. As the SLDF DropShip crews began to panic they fired indiscriminately at anything moving, damaging friend and foe alike, only to compound the damage already done when several DropShips - including Forlough's Command DropShip - made emergency lift-offs, damaging units around them with their drive plumes.
Although the Carabiniers and the Legion lost a hundred 'Mechs with another hundred badly damaged, they caused the SLDF twice as many losses, along with several DropShips and two thousand casualties, reducing the combat strength of V Corps by a third.
Having mauled the SLDF forces on Tellman IV, the Carabiniers were then deployed to the ongoing battle for Cerberus, which had became a slow grind that would continue to rumble on up until the end of the Star League invasion of the Alliance on the 1st of August 2585 with the implementation of the Treaty of Cerberus.
- Historical: Reunification War, p. 42, "Santiago Carabiniers"
- Historical: Reunification War, p. 124, "Day of Vengeance" Cite error: Invalid
<ref>tag; name "H:RWp124" defined multiple times with different content
- The Star League, p. 50, "Outworlds Alliance War"
- The Periphery (1st Edition), p. 38, "Strategy of Savagery"
- Historical: Reunification War, p. 141, "Outworlds Alliance Front"
- Historical: Reunification War, p. 183, "Outworlds Alliance"