"Only when the last xenos has been scoured from the galaxy shall the Imperium know peace."
- — Captain Do'tharri, Iron Lords 4th Company
The Iron Lords are known for their exceptionally stern demeanor and absolute hatred for all xenos life.
Ever since the 38th Millennium, it has been the duty of the Iron Lords to maintain the blockade of the Grendl Stars, confining the vile alien species known as the Barghesi within that region of space until the Imperium can muster enough resources to exterminate them as a threat to Mankind.
In recent years, the Iron Lords have battled the tendrils of the Tyranid Hive Fleet Kraken as it sweeps through the Grendl Stars, leading the Iron Lords to engage in one desperate battle after another with ever greater swarms of bio-engineered horrors.
Should the Kraken be allowed to assimilate the genetic potential of the Barghesi, the results would be dire indeed for the galaxy.
The Iron Lords have vowed in the name of the Emperor to prevent this at all costs, a vow they will honour with the life of every Battle-Brother in the Chapter if needs be.
- Grendl Stars Campaign (Unknown Date.M38) - The Iron Lords were responsible for driving back the hyper-aggressive xenos known as the Barghesi to their home in the Grendl Stars.
- Judgement of Hellenus (801.M41) - Inquisitor Hector Rex assumed direct control over the entire 279th Assault Armada of the Imperial Navy and ordered the mutant population of Hellenus purged for crimes against genetic purity. At the height of this purge, a combined strike force consisting of Space Marines form the Iron Lords, Skull Bearers and Sons of Guilliman Chapters was gathered together to confront the mutant abominations holding the enemy capital. During this confrontation, the Iron Lords contingent became tainted by the mutants' hideous gene-taint, forcing their fellow Space Marines to purge them as well.
- Hive Fleet Kraken (992.M41) - The Iron Lords had so far been successful in preventing the Tyranids of Hive Fleet Kraken from entering the Grendl Stars and thus harvesting the genetic potential of the vicious Barghesi species.
- Defence of Valedor (997.M41) - The Tyranid Hive Fleet Leviathan overrun the Ecclesiarchy world of Valedor in a matter of hours, slaughtering the entire population of pilgrims and Ministorum Adepts, as well as overwhelming a Battle Barge of the Iron Lords Chapter. A small force of Battle-Sisters from the Order of the Sacred Rose represented the only humans to bear witness to the event, having barely fought their way clear of the carnage.
- The Zeist Campaign (999.M41) - The Iron Lords answered the summons of Marneus Calgar, the Lord Macragge and Chapter Master of the Ultramarines, for a force of Space Marines to throw back the expansion of the Tau Empire in the Eastern Fringe in 999.M41. The Chapter participated in the successfully punitive Zeist Campaign.
- Entropic Field Generator - The Entropic Field Generator is a specialised entropic Force Field emitter. Since their Founding, the Iron Lords have kept an unflinching watch on the Grendl Stars where the alien Barghesi dwell, and have developed many specialised armaments with which to assist their age-old vigil. The Entropic Field Generator is one such tool, favoured even over the Iron Halo in protection against the Barghesi's vile assaults. The Deathwatch Techmarines and Forgemasters of Watch Fortress Erioch have never uncovered the secrets of its manufacture and its existence is something of a mystery even to the Iron Lords, credited with presenting the device to the stewards of the Watch Fortress several centuries ago. Regardless, the utility of the unique device cannot be denied. Any attack passing through the field generated by the emitter is assaulted by the ravages of decay, causing energy to flicker out, flesh to rot, and projectiles to lose their force.
The Iron Lords' Power Armour is painted black with red thigh plates and greaves. The rest of the armour is black, save for the Aquila or Imperialis on the breastplate which is golden. The white squad specialty symbol is indicated on the right shoulder guard or the right shin plate.
A black Roman numeral is stenciled on the centre of the squad specialty symbol, which indicates squad number.
The colour of the helm stripe indicates which Company the individual Battle-Brother belongs to, as dictated by the Codex Astartes -- i.e. White (1st Company), Yellow (2nd Company), Red (3rd Company), Green (4th Company), etc.
- Codex Adeptus Astartes - Space Marines (8th Edition), pg. 57
- Codex: Space Marines (8th Edition) (Revised Codex), pg. 56
- Codex: Space Marines (7th Edition) (Digital Edition), pg. 143
- Codex: Space Marines (6th Edition), pp. 71, 147
- Codex: Space Marines (5th Edition), pp. 29-30, 48
- Deathwatch - Honour the Chapter (RPG), pg. 127
- Imperial Armour Volume Two (Second Edition) - War Machines of the Adeptus Astartes, pp. 21-22
- Insignium Astartes, pg. 54