The Trianguli Execution

History
The forces of the insidious Alpha Legion incited an uprising against the Imperium within the Jorhelm Cluster. The Wardens of Orasks' Captain Mirex led elements from the Chapter's 3rd and 8th Companies to the jungle planet of Trianguli to eliminate the rebellion and drive the Traitor Legion from the world. Mirex's bold tactical choice at first seemed to drive the enemy back but the assault stalls when the Alpha Legion's base of operations on the world was determined to be an ancient and long-lost Imperator-class Battle Titan left from the days of the Horus Heresy.

Though still half-buried in the mud and earth, the monstrous war engine's Void Shield generators and weapons batteries proved to be operational with devastating consequences for the servants of the Emperor. Many Wardens of Orask Astartes fell in the first assault against the Titan and Captain Mirex feared that the only course open to him to end the threat would be an outright Exterminatus order against Trianguli and its people.

Fortunately for the innocents of that Feral World, aid arrived in the form of the Imperius Ravagers' Chapter 4th Company. Sent to claim the head of the Alpha Legion's infamous Daemon Prince Rangez Nightbane, the Prefect joined his forces to the remains of the Wardens of Orask Astartes on the planet. As the Imperius Ravagers launched their own attack on the Alpha Legion's bastion from below, the Wardens used their Stormravens to initiate a series of drop assaults against the secondary plasma reactors that powered the Titan's weapons. Mirex's Astartes neutralised the Titan's defences and the Ravagers swarmed into the massive war machine's lower levels.

Though Rangez ultimately escaped once more, his followers were exterminated to the last Chaos Cultist and Alpha Legionary. Though Imperius Ravagers' Prefect was obliged to continue his hunt for the Daemon Prince, Trianguli had been restored to the Emperor's light and the recovery of a battered but fully repairable Imperator Titan is no mean feat. Mirex eventually brought the Titan back to Orask, from which it was sent on to Mars.