Belphegor is a Dark Angels Interrogator-Chaplain. Taking part in the Siege of Vraks, he helped lead the hunt for the Alpha Legion Warlord Arkos the Faithless. Meeting the Alpha Legion Warlord's warband, The Faithless in battle, Belphegor saved the life of Supreme Grand Master Azrael by intervening before Arkos could strike the Chapter Master down. Later towards the end of the siege, Arkos was cornered and managed to strike down Master Yafrir. Belphegor then engaged the traitor astartes in combat, sending Arkos reeling with a single blow from his Crozius Arcanum and allowing him to be captured.