The Iron Guardians are a chapter of space marines of unknown decent. Though they are assumed to be Iron hand decent they claim to be Salamander decent do to them using flame and melta weaponry.
The chapter never really appeared until the 35th mellium appearing over a planet close to losing to a horde of orks. They burned the orks out in flame and tanks. The chapter soon turned the planet to there new recruitment world by the name of Zyst near the Ultima segmentum. It was also the time where a tau invasion came to control the planet only to be pushed off world by the defenders. The Iron Guardians chapter was contacted by the inquisition and the chapter master was brought before a court of other chapters.
His name was Adrile Mac. He stated to the judges and juries of chapter masters and imperial officers saying that the planet is under protection by the emperor's servants and he will humbly bow before the court to let them investigate to there leisure.
The inquisition went on a five month investigation.
The iron guardians gave surprising help showing everything and welcoming the inquisitors in as friends and allies.
After the 5 months had passed the investigators said the chapter was pure and there intentions in the imperials common interest.
The chapter soon took a standing with the codex astartes following it to there organization.
How ever the chapter soon took a turn for the worst when there 7th company had gone rouge. The chapter quickly suppressed it and found only half the company to be traitor while the rest had fought for there lives. The leader was a veteran sgt of there company barely managed to rally his battle brothers and fought the traitors and traitor captain in combat.
After that mess the Inquisition ordered the Iron Guardians into a massive investigation again. This time by force.
The Iron Guardians where soon quarantined for three years until the inquisition said the chapter was pure.
What happened is unknown but the chapter had a real distrust for the Inquisition and soon came to contact with the Dire Wolves in a crusade against Iron warriors and Word Bearers and made a friend ship with them becoming battle brothers bringing ice and fire to the forces of chaos.
The two chapters soon became very distrustful of the Inquisition and said that "The Emeperors servants should not have that much authority to kill the emperors servants in cold blood."
Right now the chapter fights with there battle brothers in the 13 black crusade all but two comapnies are accounted for and the current chapter master Khain took up the last chapter masters name Adrile Mac to honour the leader forever.