- "Show your enemy mercy and he shall one day seek vengeance upon you for every petty, imagined slight. Mercy is therefore a weakness; a crime waiting to be born. Mercy I have long since expunged, both from myself and my Legion."
- — The Night Haunter
The Atramentar are the elite Terminator-armoured unit of Battle-Brothers from the Night Lords Traitor Legion's formidable 1st Company led by the infamous First Captain Jago Sevatarion. Following the death of Captain Sevatar at the Battle of Terra, the leadership of the Atramentar passed to the Terran-born Night Lord Zso Sahaal. The Atramentar largely dissolved as a cohesive force in the wake of the Horus Heresy, and spread out amongst the warbands of the fractious VIIIth Legion, acting as bodyguards to various Night Lords Chaos Lords who led their own warbands of Chaos Space Marines.
During the Great Crusade no Legion of the Legiones Astartes elevated the use of fear itself as a weapon to the extent that the Night Lords Legion did. Even before the treachery of the Drop Site Massacre of Istvaan V, the Night Lords were Renegade in all but name, having entirely devoted themselves to the arts of terror and murder. At the forefront of this Legion of murderers, cutthroats and torturers were the Atramentar. This elite cadre's numbers were chosen from amongst the standard ranks of the Night Lords Legion from Astartes who had been singled out and personally selected by their Primarch for their ferocity and cruelty. Each member was known by name and reputation within and without the Night Lords Legion. During the Drop Site Massacre, First Captain Sevatar led his 1st Company elite to the surface of Istvaan V. Bronze chains wrapped their armour, leashing weapons to fists, as the Night Lords made ready for the coming signal to begin the assault upon the unsuspecting Loyalists. Following the first wave of the attack and the bloodying of the three Loyalist Legions, the second wave of "reinforcements" eagerly awaited the withdrawing mass of Loyalists on the slopes of the Urgall Depression. As the battered Raven Guard warriors staggered towards the unified Night Lords and Word Bearers force, exhausted, clutching empty Bolters and broken blades, believing their "brothers'" presence to be a reprieve, they waited in grim silence. As they voxed hails requesting medical aid and supply, the exhausted warriors of the Raven Guard and Salamanders came to within a hundred metres of their "allies". It was then that Horus revealed his perfidy and sprung his lethal trap. Inside the black alien fortress where the Warmaster had made his lair, a lone flare shot skyward, exploding in a hellish red glow that lit the battlefield below. The fire of betrayal roared from the barrels of a thousand guns, as the second wave of Astartes revealed where their true loyalties now lay.
Following the massacre on Istvaan V, the Warmaster Horus sent Night Haunter and his Night Lords Legion on a campaign of genocide against the Imperial strongholds of Heroldar and Thramas in the Aegis Sub-sector of the Eastern Fringe, thus protecting Horus' flank and delaying the Dark Angels Legion from reinforcing the Loyalists. This bitterly contested campaign dragged on for nearly three standard years. At the height of this brutal campaign the Dark Angels executed a meticulously planned ambush on the Night Lords' fleet while it was in transit across the sub-sector that saw the back of the Night Lords Legion broken and their Primarch mortally wounded after having faced his brother Lion El'Jonson once again in mortal combat. Thanks to the skilled coordination and superb execution by the Lion, the Night Lords fleet was devastated, losing dozens of capital ships and approximately one-quarter of their Legion fleet to the Dark Angels' assault. Unfortunately, the remainder of the Night Lords fleet fled the Dark Angels' wrath, taking their critically wounded Primarch with them before the Lion could finally end his wretched life. This resulted in the death of all but a dozen of the Atramentar and the capture of First Captain Sevatar and the remaining survivors. Konrad Curze fled El'Jonson's wrath, evading the Dark Angels for months, stalking the shadows within the bowels of their mighty capital ship, the Invincible Reason. Somehow, the remaining Night Lords managed to affect their escape and fled into the void.
Following the death of Sevatar during the epic conclusion of the Horus Heresy at the Battle of Terra, the Atramentar largely dissolved, which some, like the Apothecary Talos Valcoran, believed was due to Sevatar's successor Zso Sahaal being a non-Nostraman. Though they respected Sevatar's successor, they had no affection for him. When the Atramentar disbanded after Sevatar's death, their resistance to Zso Sahaal was born from something more than simple prejudice. Some of the 1st Company were Terrans, the oldest warriors in the VIIIth Legion. But there was more to it than just Sahaal's birth world. Being Terran, Nostraman, or born of any other world had never mattered to most of the Night Lords. They were divided because with their Primarch gone, this was every Traitor Legion's fate over time as the realities of an allegiance to Chaos, no matter how ephemeral, manifested themselves more strongly. Centuries later, when a member of the Atramentar was questioned by Mercutian, a squad member of First Claw, 10th Company, he replied that the 1st Company had dissolved mostly because its Astartes felt that no one could live up the dark reputation of their former First Captain. The Atramentar would serve no other leader after Sevatar died; he had made them into what they were, a brotherhood that could not be broken any other way. In the same way, the members of the VIIIth Legion would serve no single Captain after their Primarch died. It was not their way, just as most of the Traitor Legions ultimately fragmented into hundreds of different warbands. Allegiance to Chaos ultimately always bred division and fractious internecine conflict no matter how powerful its worshipers proved to be.
- Jago "Sevatar" Sevatarion - Jago Sevatarion, known also as Sevatar, "the Condemned," and the "Prince of Crows," was the First Captain of the Night Lords Legion. He was also the Commander of the Atramentar, the elite Terminator-armoured unit of the VIIIth Legion's formidable 1st Company and officer of the Kyroptera, the Night Haunter's most trusted advisors and confidants within the Night Lords Legion, during the Great Crusade and the Horus Heresy in the 30th and early 31st Millennia. A native of Nostramo, Sevatar served as Equerry to the Primarch Konrad Curze and was known as one of the most lethal warriors of the entire Legiones Astartes, his name and skill as well known as those of Ezykyle Abaddon of the Sons of Horus, Corswain of the Dark Angels, Chapter Master Raldoron of the Blood Angels or Lord Commander Eidolon of the Emperor's Children. Sevatar was killed during the Battle of Terra.
- Zso Sahaal, "The Talonmaster"- Zso Sahaal was the "Talonmaster", the First Captain of the VIII Legion's elite 1st Company after his predecessor, Jago Sevatarion, was slain during the Battle of Terra. He was known as the Unguis Raptus, "the Raptor's Claws," for his incorporation of Lightning Claws into his Power Armour, and this name was also applied to the troops of the 1st Company's elite command squad.
- Malek - Served as bodyguard to Vandred Anrathi, also known as The Exalted, commander of the Night Lords warband known as The Exalted.
- Garadon - Served as bodyguard to the Chaos Lord known as The Exalted.
- Vraal - Served as bodyguard to the Chaos Lord known as The Exalted.
- Thorion - Served as an Atramentar commander during the Thramas Crusade in the midst of the Horus Heresy.
- Orrin Valzen - Served as an Atramentar officer and Chief Apothecary of the VIIIth Legion during the Great Crusade and the Horus Heresy.
- Jakresh - Served among the Atramentar during the Thramas Crusade in the midst of the Horus Heresy.
- Tal Vanek - Served among the Atramentar during the Thramas Crusade in the midst of the Horus Heresy.
- Shadows of Treachery (Anthology), "Prince of Crows" (Short Story) by Aaron Dembski-Bowden
- Night Lords Novel Series:
- Soul Hunter (Novel) by Aaron Dembski-Bowden
- Blood Reaver (Novel) by Aaron Dembski-Bowden
- Void Stalker (Novel) by Aaron Dembski-Bowden