A Grotesque is what becomes of a Drukhari who gives grave offence to a Haemonculus and survives, if such an existence can be called survival, to regret it. Once ordinary members of Commorrite society, these wretches are dragged to the flesh-crafter's chambers and subjected to a punishment of surpassing cruelty: a slow remaking into a monster, wrought over years of humiliating and agonising surgery, that ends in a towering thing of swollen muscle and grafted iron incapable even of comprehending what it has lost.
The transformation is a grotesquery of the alchemist's art. The captive is pumped without pause full of growth-elixirs, macro-steroids and muscle-stimulants until its body bloats hideously out of all natural proportion, while injections of osseovirals whip its skeleton into frenzied overgrowth, driving jagged spines out through the skin. The forearms are opened and rebuilt around cruel blades and gauntlets that weep toxins. At the last the mind is all but excised, leaving a placid and obedient monster that will do nothing at all until its master points it at the enemy.
Loosed upon the battlefield, a Grotesque is a living battering ram, wading through gunfire it is too witless to fear and rending apart anything set before it. Now and again a specimen responds to the Haemonculi's treatments with unlooked-for ferocity, swelling larger and hungrier and more savage than its fellows until it becomes a thing the Drukhari name an Aberration, a rampaging catastrophe its keepers can barely leash and would sooner aim than restrain.