Autek Mor
Autek Mor aka "The Maimed" was the Iron Lord and Iron Father to the infamous Clan Morragul of the Iron Hands during the Great Crusade and Horus Heresy and later Chapter Master of the Red Talons. One of the original members of the Legion prior to it's reunion with Ferrus Manus, he had already developed a reputation for being a weaponsmith and an asshole. He was reputed to rule his clan company with an iron fist and for having killed members of his own legion in duels over slights to his honour. When Ferrus was rediscovered and the Legion came to Medusa. Mor took over an outlaw clan's leviathan crawler in a single night of violence and made it his. As the years went by, Clan Morragul became a sinkhole for the outcasts and unstable elements of the Iron Hands who fought and died under Mor's command. He also didn't really get on well with Ferrus, having no love for each other. As such his and his clan's reputation was shit and were generally regarded as outsiders in the Iron Tenth, of course Mor couldn't give a shit.
When the biggest family drama began, Clan Morragul was part of the second wave of Iron Hand forces to arrive at Istvaan. Unfortunately his arrival was at the same time the Night Lords, Iron Warriors, Word Bearers and Alpha Legion pressed the change team button. Though they never really liked each other Mor valiantly tried to break through the traitor fleet to rescue Ferrus, unwilling to accept his demise. Alas, he was forced to retreat and escape with a handful of survivors.
While Shadrak Meduson rallied most of the survivors and fought guerilla style, Autek Mor said fuck that and went about his own way. He would gather what forces would rally to his banner and launch a series of full-scale assaults upon worlds that the Traitors had captured or turned, allowing them to expend their strength and then destroying what remained with overwhelming force. It was a brutal strategy in which entire populations were to be allowed to fall while the Iron Hands stayed their wrath, yet it was one that made full accounting of the relentless calculus of war. With their force blunted by their invasion operations, the Traitors could be attacked at the moment of their supposed victory whilst at their weakest and obliterated without mercy.
Mor especially punished worlds that simply surrendered to the traitors without fighting. One such planet was liberated only for atomic devices to be detonated. Mor was brutal but this was nothing compared to what he did next.
Marshaling a force of Solar Axuilia as well as elements of the Imperial Fists, Autek Mor attacked the planet of Bodt, the fief world of the World Eaters. Now Mor could've done the simple thing and attacked with maximum rip and tear but, instead, he crashed the FUCKING MOON ON THE PLANET. He also took a stasis casket containing something from the vaults before the moon crashed. The entire population, traitor marines, Sarum Mechanicum and Legio Titanicus was destroyed which not only was a blow to the World Eaters' recruitment but to the overall traitor cause.
After the Horus Heresy, Clan Morragul became the Red Talons Chapter and Mor became it's Chapter Master.
TLDR: Autek Mor got shit done.