Yoran Pailsen commanded the Red Shoulder Battalion, an elite Gilgamesh Confederation unit infamous for its merciless tactics and dedication to forging the ultimate soldier through experimental methods. His leadership emphasized ruthless operational efficiency and battlefield success, dismissing ethical constraints and treating personnel as disposable assets. Under his command, recruits such as Chirico Cuvie endured harrowing training and missions with catastrophic casualty rates, engineered to isolate those exhibiting extraordinary survival instincts.

Pailsen’s fixation on Chirico arose from the soldier’s statistically improbable survival patterns in combat, prompting theories of an innate genetic trait granting near-immortality. To validate this hypothesis, Pailsen orchestrated lethal experiments—deliberately exposing Chirico to gunfire, infernos, and other fatal scenarios—to probe the limits of his endurance. These trials formed part of Pailsen’s decades-long crusade to cultivate a "supreme survivor," fueled by his research into genetic aberrations within the Astragius Galaxy.

After the Red Shoulders’ dissolution, Pailsen stood trial for protocol violations and unit mismanagement. Under Melkian Intelligence interrogation, he divulged insights into Chirico’s unprecedented resilience, declaring him a one-in-trillions genetic anomaly. Undeterred by disgrace, Pailsen pursued clandestine projects to replicate his discoveries, ultimately engineering Ypsilon—a synthetic "Perfect Soldier" intended to eclipse Chirico’s capabilities.

Pailsen’s methodologies endured beyond his military career, shaping covert experiments and intelligence strategies. His legacy remains defined by a dispassionate, calculative approach to warfare, an unwavering allegiance to scientific progress above human dignity, and a fanatical quest for martial supremacy that etched enduring scars—psychological and physical—across those who survived his command.