The Leadbelchers are ogres who have fallen in love with the noise. Each hauls a colossal, battered cannon — looted from some dwarf hold or man-city and rebuilt to ogre scale — which he crams with scrap iron, rocks, old coins, and anything else small enough to fit down the barrel, then fires from the hip in a deafening gout of smoke and shrapnel.
Accuracy is not remotely the point. A Leadbelcher volley scythes down whatever stands in the general direction it was aimed, and the ogre wielding it grins through the blast like a child with a firework. Between shots they swing the spent cannons as clubs, for reloading is slow, dangerous work and an ogre grows impatient. The guns misfire as often as not, cracking barrels and mangling the occasional hand, but a Leadbelcher counts a lost finger a fair price for the roar. No wall, rank, or nerve holds long once these thunder-happy giants open up.