Changes

Thus when Horus's forces fell on Terra itself some years later, Magnus and most of the Thousand Sons were with him. Noted to be a very small contingent of the Chaos forces, the Thousand Sons contented themselves with summoning [[daemons|daemonic reinforcements]] and casting supporting spells rather than engaging in pitched battle for most of the [[Siege of Terra]]. However, once the outer walls of the [[Imperial Palace]] had been breached, the Thousand Sons found themselves required to break down the final wards and fortifications of the inner palace itself. Advancing to the [[Ultimate Gate]], part of the legion held off Imperial counter-attacks while the senior sorcerers attempted to destroy the defences with psychic power and sorcerous ritual. This assault came to naught however, as a contingent of [[Imperial Fists]] led by Rogal Dorn arrived in the combat zone and drove the Thousand Sons off at much the same time as the Emperor himself directed the surviving Librarians of the [[Blood Angels]] and Imperial Fists to block the attacks of the Thousand Sons sorcerers.{{Fn|1}} Later a group of Thousand Sons led by Magnus himself infiltrated the Palace to recover a [[Shards of Magnus|lost shard]], but after learning this was now [[Janus|beyond his reach]] the Crimson King changed the mission to instead slay the Emperor upon the [[Golden Throne]].{{Fn|50a}} Thanks to the intervention of [[Vulkan]], his ''Draaksward'', and the pack of [[Bodvar Bjarki]] the attempt failed, and at the height of the battle Magnus fully gave himself over to the powers of chaos before vanishing from the [[Imperial Dungeon]] alongside his men. After the battle the Thousand Sons were fully committed to Horus' cause on Terra.{{Fn|50b}} Magnus next enacted a ritual in the [[Webway]] to sap the Emperor's strength and lower his anti-Daemonic psychic shield, but Vulkan journeyed into the realm to again do battle with his brother as the Thousand Sons took part in the attack on the [[Eternity Gate (Imperial)|Eternity Gate]]. After Magnus' defeat at the hands of Vulkan, the Thousand Sons ' forces broke.{{Fn|76}}