They were among the Chapter's forces sent to end rebellion the Mining World Muz. Its population lived aboard massive mining vehicles called Deep-miners and the Chaplains and several squadrons were sent to cleanse one. While fighting with the Intercessor Squad of Sergeant Raum, however, the Chaplains discovered that Muz's rebellious population was tainted by Genestealers. Raguel tried to rely this information, to the Master overseeing the attack, but his Vox-unit was being jammed by the Deep-miner. The best way to overcome this, was to claim the Deep-miner's command centre and Raguel quickly led his forces there. When they reached the command centre, though, they were met by a large Genestealer Cult horde, which included its Magus.
In the battle that followed, the tainted psyker nearly killed the Interrogator-Chaplin with its powers, until Hadariel charged at the Magus. Doing so, drew its deadly gaze upon the Chaplain, causing him to collapse, but this gave Raguel the time he needed to kill the Magus. Even with that dangerous foe dead, they were still heavily outnumbered, but luckily the sound of battle had drawn the other Dark Angels squadrons to the command centre. With their aid, the Genestealer horde was defeated, though, the jamming still continued and Hadariel had been badly wounded. As the Squadrons then left to continue their mission, Raguel chose to remain with Hadariel as Sergeant Raum promised to send an Apothecary. The Chaplain's memories had been jarred by the Magus' attacks, however, and he remembered being sent on a mission Malmar. There, he had discovered a darkness that was eating at the Dark Angels, which caused the Chapter to mindwipe Hadariel's memory. While Raguel tried to to calm the Chaplain, Hadariel claimed he remembered everything and knew what the Chapter had done to him. This caused Raguel to immediately kill the Chaplain, to keep the Dark Angels' secrets secured, though he deeply regretted having to do so.
Raguel later met with his fellow Interrogator-Chaplain Asmodai to discuss the failure of Hadariel's mindwipe. While doing so, he raged that the Chapter prevented him from accompanying Hadariel to Malmar. The world had been used as Hadariel's trial to join the ranks of the Inner Circle, which would have made him the first of the Chapter's Primaris Chaplains to do so, but he had failed under mysterious circumstances. This had caused the Inner Circle to have the Chaplain mindwiped and they had then ordered Raguel to kill him, should Hadariel ever remember what occurred. Doing so had stained Raguel's conscience, however, and he bitterly speculated that Hadariel's trial had been manipulated, to ensure that the Primaris Chaplain failed.