Editing Leviathan Host (section)

==Pre-Primarch History & Reunion==

While Marduk was stewarding his people and later crushing his enemies, his true gene-sons fought their own long war. The First Legion was a test bed and the tip of the Emperor’s spear during the early Great Crusade. Many technologies were pioneered among their number, most notably the Land Speeder and the Power Weapon. These arms remained prominent among them even until the later Crusade. Similarly, they were the original practitioners of Deep Striking and were part of what defined it as a Space Marine strategy during the early years of the legions. They were originally the standard to which the other budding legions were held, earning the moniker “Immortals”. That name, and importance, would eventually be their downfall, however. The Immortals could always be found at the front of any advance, but as the Crusade waxed greater and greater, they were gradually spread thin. Then as Primarchs began to be found, they quickly took the reins of the campaign from the Lord Commanders, but the Primarch of the First was nowhere to be found. Still the endless war pushed forward, and gradually the Immortals were worn down. Always kept at full strength so they could be the vanguard of operations, they were steadily becoming increasingly weary with the conflict. Battle hardened veterans watched waves of new recruits arrive and be lost almost as quickly, while recruits were greeted with increasingly melancholic leadership and a lack of mentorship because of the high casualties. Some of the other legions began quietly deriding them as “Immortals” because they replaced their dead so fast it didn’t matter if they lived or died.  This went on for decades, almost centuries, before their Primarch was found. When Marduk did finally arrive to greet the Immortals, their morale hung by a razor thin thread.