The Cathedral is a Retribution-class Imperial battleship, birthplace of The Church of Circrotgle. It was originally a Black Templar vessel, called the Merciless VIII, given to the Himfea Gaur -who was formerly a Black Templar- upon his mission to found a new chapter; but it was repurposed and repainted to be the fortress-monastery of the Church. It was made in the Ring of Iron of Mars, around M38. The ship has a long list of deadly encounters and planet-crashes, ultimately ending with its impact on Legacium.