House Chimaeros - Betrayal: The populous world of Donatos Primus had succumbed to civil unrest and insurrection, Chaos Cultists and insurrectionist Planetary Defence Forces seizing power with the active help of the Word Bearers warband led by the Dark Apostle Varakh'Lorr. Supported by several regiments of the Astra Militarum hailing from such diverse worlds as Cadia, Mubraxis and Tanhollis, the alliance of Adrastapolian Knights led the counter-invasion from the last Imperial redoubts.Landing in the Pentakhost peninsula, the battle-hungry Imperial Knights easily vanquished the hopelessly outclassed Traitor militia and what little armoured support they could muster. At this point, House Chimaeros and its allies still maintained the façade of being loyal Imperial subjects and conducted the war according to the plans laid down by High King Tolwyn Tan Draconis, the commander-in-chief of the Imperial war-effort on Donatos Primus. But secretly, Gerraint Tan Chimaeros was already in league with the enemy -- through control over a daemon known as "That Which Dwells In Darkness", his consort, Alicia Kar Manticos, communicated with the enemy.On the eve of the Imperial attack on the great Adamant Citadels, a series of powerful fortifications designed to prevent Donatos Primus from falling into enemy hands, it was she who communicated to Varakh'Lorr the detailed battle-plans of High King Tolwyn. Both House Chimaeros and House Wyvorn had begun to conduct the Chaos rites which would ward their own Knights from the baleful effects of a specially-engineered tech-djinn designed to cripple the Imperial communication system. Once isolated and unable to communicate with each other, the Renegade Knights would turn their weapons on their former allies, trapping the Loyalist Imperial Knights between their own guns and that of the Valle Electrum.Despite their carefully planned betrayal, House Chimaeros' attack failed to meet all its objectives. While High King Tolwyn Tan Draconis was slain -- leaving Viscount Gerraint to claim the crown of the High King -- Tolwyn's stubbornness and tactical acumen ensured that the crippled Imperial Knight Houses could still extract themselves from the trap laid for them. Attacking the encircling Word Bearers, the survivors of House Draconis, House Minotos and House Pegasson broke free, retreating to a vast network of underground storage bunkers.Acclaimed as the new High King of Adrastapol, Gerraint Tan Chimaeros ordered his own Knight, Therianthros, to be equipped with the heirloom of the High Kings, an ancient Tempest Blade ripped from Tolwyn's destroyed Knight Paladin. It remains unclear if Gerraint and his consort intended from the start to betray the Word Bearers as they had betrayed their fellow Knights, but for a few solar days the alliance between the Renegade Knights and the Chaos Space Marines held firm. The Loyalist survivors of House Draconis, House Minotos, House Pegasson and their allies among the Astra Militarum still posed a legitimate threat, especially now that they stood united behind Tolwyn's son, Danial Tan Draconis.To eliminate this growing threat, Gerraint and Alicia planned a new ambush, one that would lure the Loyalists' main fighting force out of hiding and strike them down. To make sure the Loyalists would take the bait, Alicia Kar Manticos would pose as a helpless prisoner of House Chimaeros and try to negotiate their surrender. If the Loyalists refused to give in, they would be slain in a murderous trap. The staging ground for this diversion was an abandoned Adeptus Arbites precinct fortress erected at the base of monumental cliffs. By planting Demolition Charges and other explosives within the cliff's walls, the Renegades hoped to bury their opponents alive or crush them beneath a thousand tons of rock.While his consort would spring the trap on the remaining Loyalist Knights, Gerraint Tan Chimaeros orchestrated his own coup against Varakh'Lorr, breaking his Knights into smaller units that were despatched to multiple battlefields so that when the moment came, the Renegade Knights of House Chimaeros would eliminate the Word Bearers and thus seize control of the Traitor PDF regiments and the hordes of Chaos Cultists. In the meantime, House Chimaeros' High Sacristan -- who had also turned Traitor -- was able to triangulate the position of the Loyalists' base of operations and informed his lord of their location.Rather than waste the strength of his Knights against them, Gerraint Tan Chimaeros passed the information on to the Word Bearers, who promptly assembled an army to attack those few Knights left behind by High King Danial as camp guards. Alicia's ploy failed to slay the pretender to the throne, even if the Loyalists suffered more losses they could not replenish. The survivors of the ambush at the Adeptus Arbites fortress arrived in time to turn the battle in the Imperium's favour.At the same time, House Draconis' Sacristans devised a way to shield the Imperial Knights from the Chaos data-djinn and re-establish communications with the other scattered Imperial units which were laying siege to the Valle Electrum, the power nexus that controlled the Adamant Citadels. Believing the would-be High King slain, the Renegade Knights enacted their second treachery and turned upon their Chaos allies. Save in the Valle Electrum, House Chimaeros was victorious on most fronts of this betrayal, but the fanatical devotion of the Word Bearers closest to Varakh'Lorr gave the remaining Adrastapolian Nobles time to conduct their own attack on the Valle Electrum and break through its outer defences.