Rainer Blumhardt, born a common citizen in the Galactic Empire, emigrated to the Free Planets Alliance. Following his relocation, he enlisted in the military and joined the elite Rosen Ritter regiment, specialists in close combat and infiltration. Within the Rosen Ritter, Blumhardt forged himself into a formidable soldier, earning recognition as part of the unit's "Strongest Quartet" alongside Walter von Schönkopf, Kasper Linz, and Karl von der Decken, renowned for their combined combat prowess and frequent joint missions.

His combat abilities were proven during the Seventh Battle of Iserlohn, where he participated in spearheading a critical infiltration mission targeting the fortress itself. In 800 UC, Blumhardt served within Admiral Yang Wen-li's security detail. During a diplomatic transit, their cruiser faced a boarding assault by Terraist cultists. Blumhardt sustained fatal injuries defending the admiral.

Fellow Rosen Ritter members discovered him severely wounded but still alive after the attack. His final words reflected awareness of Yang Wen-li's vital strategic importance to the Alliance: "If he's not alive, things won't be interesting from now on." Blumhardt succumbed to his wounds moments later, perishing in the same incident that claimed other Rosen Ritter guards assigned to Yang's protection.