At some point prior to the 41st Millennium, Ka'jagga'nath was imprisoned on the Imperial Cardinal World of Van Horne. The Daemon was trapped in a stasis-reliquary inside of a statue to the Emperor, within the Basilica of Saint Mariel. However, in 876.M41 during renovation work within the Basilica's inner sanctum, the statue was damaged and Ka'jagga'nath's stasis prison was disrupted. The Greater Daemon broke free, unleashing the Bloodtide upon the world, driving its citizens into a frenzied bloodlust.
For eight days the orgy of violence continued as increasing numbers of Daemons were drawn into the mortal world by the extreme bloodletting. On the ninth morning, Sisters of Battle from the Order of the Ebon Chalice assaulted the Basilica. However, some Sisters were corrupted upon contact with the Bloodtide, and most of those that resisted were slaughtered by Bloodletters atop the Basilica's walls. Ka'jagga'nath was defeated only when the Grey Knights 4th Brotherhood arrived and were able to resist the Bloodtide by slaughtering the remaining uncorrupted Sisters of Battle, mixing their innocent blood with holy oils and anointing their power armor with it, creating a shield against the Bloodtide's effects. So shielded, the Grey Knights were able to make pass through the Bloodtide to the Basilica's heart, and Ka'jagga'nath. Through the selfless sacrifice of Ordan, Champion of the 4th Brotherhood, the Grey Knights were able to cast the Daemon back to the Warp, banishing both the Bloodtide and the Daemons it bought forth.