The records pertaining to the Lamenters formative years after their troubled founding are sparse. What little remains from the period indicate that the honored Blood Angels spent the following centuries personally raising their anguished cousins to full strength under the careful tutelage and strict observation of a dedicated conclave. The Lamenters were taught their origins and traditions, trained to conduct war, and disciplined in their duties to the Imperium. The Blood Angels also regularly examined their unique heritors for any signs of heresy, the black rage, or the red thirst. They found none but did notice a propensity towards self-deprecation and an intense sense of duty. Nonetheless, the bonds between the battle brothers were strong.
Upon completion of their training, maturation of their first wave of Neophytes, and full manufacture of their equipment and fleet the Lamenters were validated for full service as an esteemed chapter of the Adeptus Astartes. With a small fleet of ships, including a Battle Barge, four Strike Cruisers, and a handful of escorts, the Lamenters set out on their mission of protecting the Imperium from enemies within and without. This brief period of time would be a golden moment, full of pride and ambition for the Chapter. This enthusiasm would not last long under the weight of the Cursed Founding.
Many of the chapters created in the 21st Founding were being purged in bloody campaigns led by the Inquisition as the Lamenters took the field. Many of the cursed chapters, still loyal to the Imperium, met their fates in diverse ways due to unfortunate turns of circumstance, a phenomenon that was reported all too often. The Lamenters diligently continued about their duties, but always under scrutiny. Observation, questioning, spying, threats, every tactic was employed by the Inquisition, short of open conflict, to fatigue the suspect Lamenters, to openly expose the heresy they assumed to be festering just underneath the surface. The Inquisition was a constant shadow over their shoulders at all times, but they could never provoke the stoic chapter.
As combat operations increased for the Chapter, addressing petitions of intervention as they could, they found themselves working side by side with Planetary Defense Forces, Imperial Guard Units, and occasionally, other Adeptus Astartes. What would normally be a venerated matter of providence, Space Marines joining a desperate battle to save uncounted souls, the Lamenters eventually became pariahs in all theaters of war as their constant Inquisitorial shadow interfered in every aspect of their work. Eventually, the stigma of the Cursed Founding would find itself among the rank and file soldiers in the campaign with many refusing to fight with the Lamenters. On occasion, in the most extreme circumstances and usually at the provocation of the most superstitious units, the allied army would turn on their benefactors amidst the battle, forcing the Lamenters to retreat. Besieged on all sides, rather than fight those they were commissioned to protect, withdrawal for the chapter routinely meant running headlong into the enemy force and breaking it, but at an extremely high casualty rate to themselves, simply to escape their supposed confederates.
The chapter became embroiled inside internal politics, unable to escape the stigma of their origins. The frustration and distress turned into cynicism and despair among the brethren. Their duties to protect the Imperium were being obstructed by their own charges. This caused an extreme depression in the ranks of the dedicated marines who only sought to help. Concern began to spread about the Black Rage and Red Thirst becoming manifest within the Chapter if their unfortunate destinies could not be turned around. The situation had become desperate and a choice had to be made. The chapter held debates presided over by the Lord Commander and the Company Captains. The entirety of the Lamenters would have a voice in the matters and cast a vote for their future and where they believe the Chapter would best serve the Emperor. Once the forum was closed two decrees were issued.
The first was to remain mobile, becoming a dedicated, fleet based, crusading chapter, much like the Black Templars. They immediately ceased their search for a suitable planet to call their own and recruit Neophytes from. The Lamenters concluded that any planetary population under their protection would immediately become threatened by their very presence either by themselves or at the behest of the Inquisition. This way the chapter could more closely manage its own affairs with minimal outside influence and loss of life. The second decree was that the Lamenters would leave the Imperium proper, traveling to the Galactic West along the fringes of human territory and crusade alone against the enemies without in the name of the Emperor – a self-imposed exile for the good of others.
The Lamenters broadly found success in this endeavor. Without interference from the Inquisition, the dishonor of the Cursed Founding did not pursue them into the outer fringes. The chapter was potent in combat and found many victories, amassing a chronicle of triumphs larger than many Space Marine chapters entire histories. The bulk of their campaigns during this period were waged against Orks and Drukhari that harried human settlements in the region. Many of these settlements were cut off from Imperial support after the onset of the Horus Heresy, spending millennia simply trying to survive. Restoring order to many star systems that had only known war and endurance, the Lamenters found many allies including an Adeptus Mechanicus Forge Fleet and numerous human volunteers to become Neophytes in the Chapter.
With the exploration of these strange and isolated sectors of space, the chapter discovered numerous treasures and relics forgotten by the universe. The Lamenters fleet, after centuries of fighting in the fringes, had managed to become a massive, discordant assemblage of ships with hundreds of thousands of crewmen, families, and serfs all dedicated to the undivided cause of the Lamenters.
The time would be recorded as trying, but esprit de corps would remain high, forming lasting and deep, meaningful bonds with one another, something Lamenters would never struggle with even in the darkest times. Despite these seeming favors of fortune, the battle-brothers found themselves descending down a path of melancholy within their ranks. There were no signs of the Black Rage or Red Thirst as of yet, but inescapable despair and sadness continued to grow within as the pains of those they couldn’t help around the galaxy became a burden on their psyches.