Skull Cannons are Daemon Engines of Khorne forged from the monstrous soul-forges that fuel Khorne’s endless wars. They are sentient but desire nothing more than to feel the crunch of flesh and bone underneath their spiked wheels, and give praise to the Blood God with every foe torn to shreds within their grinding maw. The skulls of their victims are kept intact and are fed into the great cannon mounted atop the machine where they are infused with a fragment of Khorne’s ever-burning wrath, coated in a pitch of boiling blood and fire with an ear-splitting roar towards the enemy ranks. Piercing laughter peals from chattering jaws before the missiles slam home and erupt into a thunderous fireball that sends broken and charred bodies spinning through the air, a sight that has broken the will of many mortal warriors and even those that do not scatter will break upon the sight of the Skull Cannons racing towards them over a sea of ruined corpses with a cloud of gore erupting behind. 
Two Bloodletters who oversaw the Skull Cannon’s creation in the furnaces beneath the Brass Citadel ride this into battle, shovelling fresh skulls into the cannon’s maw and directing its spiteful rage as best they can, taking a creator’s pride in its every atrocity, prompting it onwards to claim more souls in the name of the Blood God. While even a single Skull Cannon is formidable, an entire Gorethunder Cohort can break even the most stalwart of enemies.