The forges of Mars worked ceaselessly to produce an endless torrent of war machines during the Horus Heresy, both for the Legiones Astartes and Solar Auxilia, and for their own standing armies. Recreated from ancient schematics, and armed with cruel and destructive weapons plucked from the Dark Age of Technology, these machineries were deployed all across the galaxy, in the interests of both Mars and those who had courted their power…
Hold on, is this starting to feel a little déjà vu?
Perhaps the message has been waylaid by the volatile whorls of the Warp… but your Mechanicum armies in Legions Imperialis are about to receive some heavy support in the form of two new boxes of tanks.

The Krios Squadron is a box of six tanks which can be built with your choice of several horrible weapons from the Tech-Priests of Mars. It comes with six trusty lightning cannons and four nasty rad-scourers.
Four pulsar-fusils and their accompanying shielding are also on the sprue, in order to make four Krios Venators instead. These relatively short-range weapons transform the mobile Krios chassis into a high-speed tank hunter. All variants come equipped with volkite caliver sponsons.

Ranged reinforcements arrive via the Karacnos Assault Tank Squadron, which contains four assault tanks armed with radiological mortar batteries. Created to help soften up the core of biological enemy forces ahead of the primary assault, the Karacnos can hold its own against light armour with a pair of lightning locks.

Rules can be found in Warhammer: The Horus Heresy - Legions Imperialis - The Rise of the Dark Mechanicum, and you can field them for the loyal Mechanicum Taghmata or the seditious-and-spiky Dark Mechanicum.