4th Black Crusade

During the 4th Black Crusade, known also as the El’Phanor War, Abaddon the Despoiler launched this incursion into the Imperium in 001.M34,  his Black Legion besieging the great Citadel of Kromarch. Abaddon led the charge against the adamantium gates of the famously unbreachable citadel upon the world of El'Phanor. Only one in ten of Abaddon's spearhead reached the gates before they were trapped by Heavy Bolter fire. Utilising his Daemon Sword Drach'nyen, the gates of the citadel proved harder than diamond, but they split apart like cordwood before Abaddon's dolorous blow. In an orgy of violence, the Traitor Legions and their daemonic allies fall upon Kromarch and his kin, extinguishing their ancient line forever.

History
The world of El’Phanor was astronghold of the Cadian Gate and a key defence against raiders trying to slip out into the Segmentum Obscurus. Commanded by the Kromarch, it had repelled countless attacks in the centuries since the Horus Heresy. Central to the defences of El’Phanor was the Grand Citadel of the Kromarch, overlooking the vast fertile flood plains of Arabor. The Black Legion descended upon the world like a plague of darkness, half a dozen warbands of the other Legions slavering for blood in their wake. The Imperial Guard struck repeatedly at the attackers, their assaults supported by massed artillery from the citadel that remained long beyond the reach of the Traitor Legionaries. During this Fourth Black Crusade Abaddon personally led the charge against the citadel’s adamantium gates through a storm of bolter rounds and exploding artillery shells. Only a fraction of the Bringers of Despair (Abaddon’s Terminator-armoured elite personal bodyguards) made it to the gates, the great obsidian road to the fortress littered with bloodied and broken Black Legionnaires.

Trapped before the gate, the Traitors hammered against its mighty doors even as the Guardsmen swept their ranks with fire from above. Raising Drach'nyen over his head Abaddon struck the gate and the Daemon weapon split it like cordwood. With the gate sundered, Abaddon and his followers spilled into the fortress, butchering and dismembering all before them. Abaddon himself took the head of the Kromarch, tearing it from his shoulders in a bloody shower of gore before holding it aloft in triumph. Summoned by the nexus of death within the fortress and this final sacrifice, hungering Daemons ripped free of the Warp and added to the pandemonium. When the last Imperial soldier was hacked apart, the Forces of Chaos fell upon themselves, lost in the joy of slaughter. Daemons and traitors feasted on the ravaged flesh of El'Phanor until it was a dead, wasted planet, and Cadia was left with a chink in its armour.