Collegia Titanica - 41st Millennium: Siege of Vraks (813-830.M41) - During the infamous Siege of Vraks, a Legio Astorum ("Warp Runners") Titan battlegroup provided the Imperial 88th Siege Army with its heaviest firepower. Deploying 22 Titans of the Reaver and Warhound-classes, the commitment of this battlegroup in support of the 12th Line Korps was the decisive factor in breaking through the inner defence lines during the Kagori offensive on Vraks Prime. The High Princeps Rand Drauca and the Warp Runners continued to support the campaign on Vraks on numerous occasions, and were heavily engaged again when the Red Scorpions Chapter captured the breach in the central Traitor keep's curtain wall, matching weapons and armour with the Traitor Titans of the Legio Vulcanum I. The exact numbers of enemy Titans was not identified, although post-battle reports claim 14 enemy Warhound and Reaver-class Titans were destroyed during the campaign. As such, the Legio Vulcanum I paid a heavy price for its involvement, and the Legio Astorum could claim a famous victory over its ancient enemy.Badab War (912-913.M41) - The Chapter Master of the Astral Claws, Lufgt Huron, the "Tyrant of Badab," sought to have the Badab Sector secede from the Imperium in protest against the Imperium's continued attempts to use the resources of the Badab Sector outside the region rather than dedicating them fully to the defeat of the forces of Chaos and xenos threats that emerged constantly in the Maelstrom Zone. This major rebellion involved several Space Marine Chapters who turned Renegade and sided with the Tyrant in his mad cause. The world of Angstrom was a highly militant minor Forge World containing a significantly independent Adeptus Mechanicus presence situated at the edge of the Maelstrom Zone, and by this web of kinship the Legio Crucius became involved in the Badab War's savage closing campaigns. The Legio Crucius forces deployed to the siege of Badab Primaris itself, comprised of three full maniples of Titans, some fifteen war machines in all, commanded by the Warlord-class Titan Hell's Daughter and High Princeps Cadmon Krom. The Titans' principal task in the battle was to smash heavy defence points in Badab Primaris' hive cities and industrial zones and crush major pockets of resistance when encountered, a mission they undertook with great relish, fully living up to their Legio's long-standing reputation as savage city-breakers and world burners. The Legio Crucius accounted for untold casualties and devastated the remaining Secessionist heavy armoured forces. The Titan Legion suffered only three losses during the engagement despite the heavy resistance they encountered, and managed to recover all but one of their wrecked Titans in the anarchic retreat from the planet by the Loyalist forces.Third War for Armageddon (998.M41) - Ork Warlord Ghazghkull Mag Uruk Thraka launched a second and even more massive Ork WAAAGH! to conquer the Imperial Hive World of Armageddon in 998.M41. As the battles raged on the planet, Ghazghkull unleashed another of his carefully prepared surprises. Incredibly, dozens of Ork Roks (asteroid fortresses) began to descend from orbit. The Roks made landings in the verdant equatorial jungles of the world and across the continents of Armageddon Primus and Secundus. Many were lost to ground fire or accidents but each one that survived became a bastion for the Orks, a rallying point and a ready-made fortress. Besides their formidable armaments, the Roks contained giant teleport arrays. These were employed to teleport down Ork reinforcements, including Gargants and Greenskin heavy artillery, in an endless stream. Commissar Yarrick personally led attacks by regiments of Cadian Shock Troops supported by the Titans of the Legio Ignatum and Legio Metalica, which destroyed several of these fortresses. During a ten-day battle that raged over the Diabolus manufactorum complex and proved to be one of the most fierce of the Third War for Armageddon, Titans from the Legio Crucius engaged the Gargants of the Warlords Burzuruk and Skarfang. Six Titans and eight Gargants were utterly destroyed in the fighting and many others needed many solar months of repairs before they could fight again. The Diabolus complex was wrecked during the battle, its foundries and machine shops blasted apart or crushed underfoot by the giant fighting machines.13th Black Crusade (ca. 999.M41) - When the forces of Chaos assaulted the world of Cadia during the 13th Black Crusade in ca. 999.M41, the Titan Legions stationed on the worlds surrounding the Eye of Terror helped in the defence of that beleaguered Imperial Fortress World. Many other Titan Legions, a number of them unleashing their entire strength, were transferred there to face the Chaos onslaught.