Operation Seraphim

Operation Seraphim was an Imperial defensive campaign conducted by the 131st Truskan 'Frostrangers' Regiment in defense of the Cadian System against attacking Drukhari corsairs, who had taken advantage of the mayhem caused by the invading Forces of Chaos during Abaddon the Despoiler's 13th Black Crusade.

Background
What would ultimately prove to be Lauri Rinne's last campaign, Operation Seraphim was launched in response to Drukhari raiders attacking areas surrounding the Cadian system. Taking advantage of Abaddon's 13th Black Crusade, the Drukhari launched multiple strikes out of the Webway, taking thousands upon thousands of human prisoners, both civilian and military. Given their experience in combating the Aeldari, the 131st were assigned to a leading role in the operation. Initially meeting with great success, the Truskans were ultimately outmaneuvered and crushed. Colonel Lauri Rinne was killed in action, the rescued prisoners were executed, and the 131st Truskan was almost completely annihilated. However, for their part, the Drukhari were made to pay dearly, and the prisoners were ultimately rescued from a horrific fate in Commorragh. Thus the surviving Truskans considered it to be an extremely pyrrhic victory.