Upon their backs running parallel on either side of their spines rows of bone pistons constantly pump and belch out a sickly blue smog which also flows from between their jaws with every rumbling breath.
Down the centre of their chests they have a set of teeth going from the base of their neck to the bottom of their ribs like a macabre zipper.
The vast majority of Tyrant Wyrms have a variety of brutal and numerous scars on their bodies.
Their horns, of which there are six, curve and coil about themselves to form a crown-like structure.
They have a crocodilian head with all of their crooked sharp teeth always exposed and their eyes glow brightly either blue, red or purple.
The older a Tyrant Wyrm is the more emaciated it is and the more purplish black their smog is and the more pistons they have on their backs and splits and breaks in their scales constantly ooze a black mire when they become very old though they become even stronger.
Wyrmlings are simple pack hunting creatures, nothing like their elder forms, technically, living breathing beasts and little more intelligent than an average dog they are spawned from the mire that their elders create from their persistent presence, growing as an embryo within the corrupted earth before eventually digging themselves out. Tyrant Matriarchs greatly accelerate the rate that these embryos develop simply by proximity. Wyrmlings while mostly unintelligent obey the orders of their elders without pause.
Tyrant Wyrm adults have learnt the beginnings of the Black Verses, becoming attached to the collective subconsciousness of the rest of their kind, shedding their life and pack mentality, becoming unliving monstrosities of corruption and destruction and being much more inclined to dwell on their own away from others of their kind, only working together with others when either a greater power than the Wyrms themselves command them or a particularly ambitious Great Tyrant rallies a group of them.
On the very rare occasion several Tyrant Wyrms will aid each other in raiding and destroying a holy site that a single one of them can't handle alone.
Most Tyrant Wyrm adults will take on a "title" which also shows what they're more capable of.
Dictator Tyrant Wyrms are more muscular and hardy than the average Wyrm, able to take on even larger dragons with relative ease, their smog has a more acidic effect than mind affecting, the Mires' they dwell in are better at draining the strength of non-Wyrms.
Vizier's are physically weaker than most of their brethren but are more capable with the Black Verses, using them to tear the minds and spirits of even the hardiest foes apart, their smog has less of an acidic effect but is very good at clawing into the minds of undead and can raise the corpses of those they breath over, the Mires' they dwell over are more likely to raise undead.
Great Tyrants are terrible elder versions of Tyrant Wyrms, they have plumbed the depths of the Black Verses and even added to them with their own variations, colossal and cruel they are the one thing all Tyrant Wyrms aspire to be.
Tyrant Matriarchs are very rare variations of Great Tyrants that grow even larger than any others of their kind and have the ability to spawn armies of Wyrmlings when they decide to nest within the earth.
All adult variations of Tyrant Wyrms are technically undead, unaffected by death magics or unholy magics designed to harm neutral or holy entities.
Wyrmlings however are living creatures and are affected by all the same things other living beings are affected by though they are immune to non-magical disease.