Breacher Siege Squad
This page is for the Legiones Astartes shield walls. If you are looking for the page about the Imperial Guard unit that blows shits up, please see Breacher Squad.
A type of Legiones Astartes unit used during both the Great Crusade and Horus Heresy, Breacher Siege Squads were, as the name suggests, a specialized unit of Legion Tactical Marines geared up for sieges and fights within Zone Mortalis areas, though they were also used in void warfare (especially when it came to ship boarding). Essentially, these guys were trained exclusively to fight in the most hazardous places the battlefield had to offer.
They were clad in void-hardened versions of Mark III "Iron" armour, as well as armed with Boarding Shields and an array of assault and siege weapons such as Graviton Guns, Lascutters, Volkite Chargers, Flamers, and Meltaguns. Breachers had better chances of survival than standard Tactical squads and could reliably achieve objectives in these areas (though considering how terrifyingly excruciating places Zones Mortalis were even for the then young Legions, it says a lot). Some Legions (like the World Eaters, Imperial Fists, Salamanders, Iron Warriors, and Iron Hands being the most prominent ones) were geared up specifically for Zone Mortalis battlefields and had large numbers of these specialists.
In the modern, post-Heresy Imperium, Breacher Squads were phased out and replaced by more effective Indomitus Termies, though it was part to the strains of extreme fights in the battlefields the Breachers operated that resulted in constant maintenance issues. This also what propelled the cog boys to accelerate the development of Terminator Armour, which, although more effective in close-quarters battle, was both much more time-consuming and resource-intensive to manufacture and train marines in its operation than Breacher Squad equipment.
Although Breacher squads no longer exist in the 41st Millennium, the combat bonuses that such shields grant against melee-focused forces such as the Orks and Tyranids are substantial, even more so in confined environs. Depending on the battlefield requirements, be it Zones Mortalis or acting in a Siege Vanguard, Tactical Squads can still be issued with Boarding Shields or "Siege Mantlets" and can be equipped with void-hardened armour where necessary, largely fulfilling the same role as the old Legion unit. This is probably the reason why "Breacher Squads" no longer exist as a permanent unit, as codex Tactical squads can just fulfill the role whenever required of them, which is more efficient in a Chapter of multi-role companies.
Specialist Breaching Formations[edit]
Phalanx Warders[edit]
In the Imperial Fists Legion, breaching and siege units formed a core part of their organisation and training. The VII Legion may have even pioneered the use of Breacher Squads as a regular formation, as Horus was said to have noted their effectiveness in battle during the early Great Crusade and adopted the practice of arming some of his squads with breacher shields afterwards.
The Phalanx Warders were an elite company of Breacher-trained Astartes who were nominally assigned to the defense of the Phalanx, though they were frequently dispersed to other VII Legion units across the galaxy to keep their skills sharp and to also provide an immovable line of defense. They were most often found in the kind of close-quarters, ship-to-ship boarding actions in which the Imperial Fists excelled. Indeed, the unique Imperial Fist Rites of War frequently feature Phalanx Warders as a core part of their battleforce. Aside from their shields, the Phalanx Warders carried power axes and bolters as standard kit, though they also employed thunder hammers, special weapons such as meltas and flamers, and Solarite power gauntlets.
Medusan Immortals[edit]
A specialized unit of Breachers that were unique to the Iron Hands Legion, Immortals were Iron Hands who had been shamed by experiencing defeat or suffering grievous wounds (but not grievous enough to put them in a Dreadnought) and who were given Breacher equipment along with very extensive cybernetic augmentation. Pre-Heresy Iron Hands had a very rigid and extreme set of standards that promoted strong-willed individuals and weeded out weaklings. If a Marine was, as mentioned before, shamed in either of the above ways, their Primarch would strip them of any ranks and titles, give them a serial number, and remove them from their original companies to fight on their own as, essentially, living marks of shame.
For such Marines, being an Immortal was the only way to gain redemption in the eyes of their Primarch and brethren, usually in the form of an honourable death in combat and thereby a final chance at glory. Formations of Immortals were often treated as forlorn hopes (i.e., units that were first into a breached fortification or the entrance into a Zone Mortalis and not expected to survive due to the often-ferocious defenses and cramped environments they would encounter), and accordingly the Immortals fought with determination in warzones so extreme that even standard Breachers would have had little chance of coming back alive.
During the Horus Heresy, the ranks of the Medusan Immortals swelled dramatically with embittered volunteers after the Drop Site Massacre, as the survivors of that battle saw the deaths of Ferrus Manus and the Clan Council as their greatest shame and humiliation, a failure beyond any hope of redemption or forgiveness. However, those who came from Clan Morragul were allowed by Autek Mor to fight alongside their brothers (which was actually unusual). And unlike other Immortals, they were allowed to wear a red talon symbol to further distinguish themselves (and these Marines were the base on which the Red Talons Chapter would be founded).
Despite these inauspicious beginnings, Immortals were not in fact generally equipped as expendable units, useful only to shed as much blood of the enemy's as they could before drowning in their own while carrying only the weapons they could scavenge, with more capable equipment assigned to "worthier" units. The fact that Immortals had extensive cybernetic augmentations allowing them to infrequently endure wounds that would have downed unaugmented marines while remaining combat-capable, as well as the fact that they could all be equipped with the increasingly-uncommon Volkite Chargers, allowed them to retain a certain tactical niche within the environments they were suited for, and allowed Iron Hands forces another option when Terminator armour was too valuable (as it inevitably became after the Dropsite Massacre) to deploy in close-quarters battle situations. It is also evident that enough Immortals survived repeated engagements to begin to adapt to and specialize in their preferred combat environments, eventually learning to forego the usual "run them down" tactics ill-suited for their Void-Hardened Armour, and instead adopting "gun them down" tactics against fleeing enemies, so whatever Ferrus Manus originally intended, the record is clear that the Immortals eventually became a useful and experienced combat asset in their own right.
Praetorian Breacher Squad[edit]
The Smurf's own take of a Siege Squad. This time, their Roman Cosplay has gone completely overboard with the Praetorian Breacher Squad, as they eschew ranged weapons entirely for some good-old fashion fisticuffs. They are close-combat wall-huggers, making them formidable defensive units as anyone trying to LEEROY JENKINS them in CQC will get a face full of shields, power swords and power axes. Whilst this makes them deadly in defensive formations, on the offense...while...the lack of range weapons will start to really feel its pinch on these guys.