While suspected to have been founded during the Age of Strife, it is generally believed that the Legion was destroyed in the opening days of the Schism of Mars, though elements of it are known to have fought during battles later in the Horus Heresy.
At the outset of the Horus Heresy, the Warmaster Horus sent the Dark Mechanicum representative Regulus to Mars to secure the tentative support of the Fabricator-General of the Mechanicum, Kelbor-Hal. Regulus convinced the Fabricator-General of the Warmaster's resolve to support increased autonomy for the Mechanicum against the autocratic rule of the Emperor of Mankind.
As a show of his appreciation for the Fabricator-General's support, Horus provided information to Kelbor-Hal that allowed the Tech-priest to open a repository of forbidden knowledge known as the Vaults of Moravec, which the Emperor had ordered sealed.
When this repository was reopened, there was all manner of forbidden arcane knowledge and weaponry that had obviously been tainted by the corrupting influence of Chaos. Soon the corruption spread throughout the forges and temples across the Red Planet as scrap code -- Chaos-contaminated digital source code that was infected with an arcane computer virus.
The scrap code infested the logi-stacks and Cogitator (computer) archives of the Mechanicum, causing literal Chaos to emerge in any Cogitator system that was networked to one of its infected counterparts. The Fabricator-General and his Dark Mechanicum allies used this disruption to marshal the strength of their forces, intent on bringing the rule of Mars firmly under their control.
Infected by this vicious scrap code, the Titans of the Legio Agravides and the Legio Fortidus met their end when their Plasma Reactors went critical and exploded, destroying their fortresses and eliminating these once-proud Titan Legions from the roster of Loyalist forces. In later years, this night would become known in Adeptus Mechanicus legends as the "Death of Innocence."
- Battle of Ice World Tralsak (011.M31) - The shallow, frozen oceans of Tralsak were flash-boiled to steam by the fury of god-engine war as Loyalist Titans of the Legio Atarus and Legio Agravides clashed with the Traitors of the Legio Magna and Legio Victorum even as the Loyalist Shattered Legions and Traitor World Eaters fought across the disintegrating landscape of ice floes. Ultimately, outright victory eluded both sides, and each used the cover of the world-enveloping fog thrown up by the destruction to extricate their forces and redeploy them elsewhere. Nevertheless, numerous supporting Knights of both sides remained to fight a war in which neither would concede defeat.
None listed in current Imperial records.
- Princeps Tevera - Tevera was the Princeps of a Warmonger-class Titan. During the Horus Heresy she was instrumental in the formal establishment of the Imperial Adeptus Mechanicus, separate and distinct from the Chaos-tainted Mechanicum of Mars.
The colours of this Titan Legion are not listed in current Imperial records.
The badge of this Titan Legion is not listed in current Imperial records.
- Adeptus Titanicus - The Horus Heresy: Rulebook (Specialty Game), pg. 17
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