Throgmaw, the Gutworm
Unlike most demons, who dwell in Hell, Throgmaw churns and writhes through the belly of the earth, tearing through rock and dirt in its ceaseless quest to consume and digest.
Throgmaw in appearance is a large, segmented worm, perhaps the size of a small train. Each segment of its long, pallid body seems to sprout from the previous part, a ring of sore, bulging teeth surrounding the squeezing flesh of the joins; each section of the worm vomiting forth the next. The mouth at the front end is terrible indeed to behold. Rings of tusk-fangs, pulsing, bulbous flesh, and a raw sphincter of flesh in the deepest part of its gaping jaws.
Perhaps by its appearance you might consider it a simple animal, or at least simple in its desires to consume and devour; and you would be horribly, tortuously wrong.
For most, admittedly, the worst fate they can expect from the Gutworm is that struck down by his weight, they will feel him descend from above and tear open their bellies and abdomens, having their meats and offal drained from them, and the ragged remains discarded like so much useless cloth. For those worthy enough to actually acquire some sort of measure of attention from the worm, a far worse fate remains.
Some special few, chosen according to principles known only to the Grand Maggot itself, will disappear in one end, and reappear at the other, imperceptibly changed, in half of cases at least. Half of the time the victim will emerge apparently unscathed by their ordeal, though eventually it will become clear that any shred of humanity they may once have possessed is gone, wholly and utterly. They are now monsters in the flesh-garb of the victim. The same is true of the other half of those special victims of the Worm, who emerge again, seemingly unscathed. However, it will only take a minute or two before they spasm and collapse, shrieking and howling as their flesh warps and contorts, never holding a solid form for more than a moment, never settling, always changing. These horrible, ever-shifting beasts quickly descend into a madness that ends only with its death, and involves the destruction of everything that isn't stone or earth as long as it continues.
Throgmaw will also sometimes leave behind tiny, wriggling grubs in his wake. Do not touch them; they can burrow through flesh and skin in an instant. This isn't even the worst part, only an unlucky few will be slain by the maggots chewing their flesh to ribbons even as they grow to replace the lost meat until the worm is all that is left inside the skin-suit. Most will survive well into the time when the maggot eats its well up into the skull and gobbles up all the delicious pinkish, folded brain-meat, leaving the Maggot in control of the now vacant corpse. Such controlled bodies never quite seem to have much of a purpose, they stumble about unable to speak or really move with much grace at all, appearing to most as more mundane undead servants. But, they seem to be acting beyond simple random impulses; they have a cruel and despicable mind and will, eager to inflict pain and death where-ever they can.
Solomon, the Gilded King
Of all Demons, Solomon is the most vile in his excess. Even in the realms of mortals his form is know; a pallid wretchedly wizened man, skin like leather, eyes shrunken down to pin-pricks. His nails are like tree roots, and his bald head creaks beneath the cold dry skin that stretches over it, his spine pokes out of his back in ragged tears.
And yet, he is always bedecked in sickening amounts of gold. His robes are lacquered in it, his staff shod in exquisite and intricate lucred murals, his hands weighed down with wicked rings. He sits hunched over in his vast, high throne atop a vast mountain of riches of all kinds. Other than he, his vast court is empty; he could tolerate not even the possibility of theft.
What demon-servants he does have cower and shake beyond the doors of his bright-shining sanctum, waiting anxiously for his bellowed commands. They respond immediately and hurriedly; those showing their "disloyalty" are entombed in gold.
In ancient stories, there are, or maybe were, ways for men to become demons. Solomon was the first and greatest of them. Born a slave, he eventually found consort with the emissaries of Hell, and bought himself a throne and eternal life at the easily paid price of all he knew to be destroyed by fire. The city he was chained in burned as he transcended mortal life, gleefully watching as that which he despised was reduced to cinders, even as his mortal form failed. Others say that it only cost a single life, unwillingly given, but given all the same.
Either way, now he rules as a king among demons, rich beyond any conceivable imaginings, powerful beyond the dreams of men. And yet, still he hungers, still he craves, still he desires. His courtly visits (he never allows any entrance to his domain) to other demon lords are lavish and extravagant, but they are never enough. The gifts and tributes he receives from the more servile lords are accepted through gritted teeth and fierce disappointment. He is never grateful.
Unlike almost all other demon lords, there are no tales of him in battle, none of iron-clad heroes kicking in the doors of his courts, none of wise and sagely mages blasting him to smithereens with powerful magics. Only of their victories, of their boasts that they and they alone could defeat Gold-Crazed Solomon, and steal his treasure. Their towers are indeed luxurious and their hordes vast, but vaster still are the vaults of Solomon, and he has never had to raise even a finger in his own defense...
Quorus is a bloated beast of a demon, a great engorged sac hanging obscenely from a insectile body, fibrile wings beating furiously to keep the whole wretched mass afloat. The sac hanging beneath the body, fully the size of a horse, is covered in altogether too many mouths, some gnashing slowly, others hanging, drooling, screaming, thrashing. The body of the creature bears a ever-shifting set of round, glistening insect-eyes, endlessly peering at you.
A ring of thin, segmented legs crowns the area above the mouth-sac, but they're too short and pathetic to actually achieve anything.
Strangely enough for a demon of Quorus' potency, the majority of its servants are non-demonic, idiot-slaves foolish enough to say their own names within hearing distance of Quorus. The lot of the Name-Slaves of Quorus is to tend to the sore and wretched mouths of the Demon, to carefully and diligently copy down the mad ravings of the more independent mouths, and to lay down their lives for the Demon Lord if needs be. There are a few demons amongst its ranks, but most are wily enough to avoid it; not even demon lords are immune to Quorus' dominion should their names be spoken. Demonic Name-Slaves rarely do anything of worth, Quorus is content to force them to demean themselves for its pleasure.
In desperation, Quorus can bite off its own tongues. They wriggle and spasm with frightful purpose, and can even leap a good distance. Each tongue bitten of in this way releases the word that was bound to it, constantly for a good few minutes, effectively deafening anyone in the area and totally disrupting communication and magical incantations. The tongues can sting those they pounce at like a wasp, and causes further tongues to sprout from the wound. They flap uselessly and occasionally dribble. Should a tongue manage to get inside someone's throat, that person will almost certainly suffocate, and return as demon-spawn of Quorus.
When it croaks, it is deep like the groan of splintering wood, or grinding tectonics. And as the throat sac stresses and bulges with the croak, so do the Demon's boils.
In the vast circles of hell, Buboskos' court is something of a meeting ground. Many weaker demons feel safe(r) in the stale-pits beneath Buboskos' filth-throne, which rises up like a heap of phlegm and bile. Beneath his stern and unwavering gaze, nothing goes unnoticed. Every scale and fiber and fleck of skin is noted and taken, in case the visiting being earns the ire of Buboskos.
Should you anger him, his gaze will not change, he will not react, but one of his servitor-demons will slink into action, pick up the leavings that inevitably remain. These will be fed to Buboskos, and he will breed a copy of the perpetrator. It is loyal to him, and is created for a purpose; usually the destruction of its originator if Buboskos created it. When the boil-simulacra has completed its task, or is slain, it dissolves slowly, over the course of hours into the thin yellowish ichor that birthed it. It is possible to convince Buboskos to create a boil-simulacra for you if you can provide both something of the creature or item you want copied and something of value to the Toad-Beast. Demons never do anything for free of course.
Buboskos' demon thralls are for the most part as pestilent as he is, covered in boils and weeping sores. They are hunched, and lope more than walk; they are still somewhat human-shaped unlike their patron, but they are somewhere in between. They record who visits when, and will pick up anything that a visitor leaves behind with delicate pincers, just in case. Their grins are altogether too wide, and their tongues just a little too prehensile. Its more than a little bit uncomfortable when they shake their hand with it. Mostly however, they are somewhat hospitable to the visiting demon and mortal traveller alike, though should violence break out, they swarm like flies around their master, defending him with sheer body mass.
If anyone should try to attack the Bloated Beast, or commit some foul treachery so unforgivable its perpetrator should be immediately extinguished, it will remain as inscrutably calm as it ever does until suddenly like a bolt of lightning its mouth will rupture, spraying caustic slime over a goodly area before it, and a tongue like a dragons head will leap forward at impossible speeds. Before the profligate can even move the tongue will open, its moray-maw vast and ringed with a thousand thousand teeth set in the tongues sickly pink flesh, and in an instant, the victim is gone, and so is the tongue, and a new boil will blossom on the Bloated Lord's hide.
Yggdrisalia, the Lady of Roots
The fair Lady of Roots barely counts as sentient most of the time. She is about a mile tall, and a half mile wide at her highest, more than seven wide at her base, and possibly bigger beneath the basalt soils of Hell. Her trunk is like flesh left to calcify over uncountable millennia, and indeed, the higher you climb, the softer and more porous it is. The branches are positively soggy and limp, drooping down like willow branches after arcing lazily through the air above. Her roots are like insect limbs, segmented and thin, compared to her trunk that is. They stab down into the earth and wind through it like cancer, arching above the surface sometimes. They bleed if cut, a thick blue lava that flows in the way that rock doesn't.
She has flowers too, and fruit, but they appear only rarely. Some say it is with the birth of a new Demon Lord that her flowers bloom, and with each mortal transcended to Demon-State that her fruits ripen and grow heavy on the branch. Some say that to drink the tea of her petals is to life eternal, and that to gorge on her fruits is instant death, or perhaps lingering death. Planting the seeds from her fruit causes devil-infantry to spring from the ground, or perhaps a temple dedicated to the infernal pantheon, or even a further flower with tongues of flame for head and leaves.
They say it is she that will end the world, her tendrils encompassing all, spread all throughout beneath the feet of men where none can see their end coming, then squeezing, splitting the earth open like a ripe peach. Others murmur that instead she will merely drink the earth dry, shriveling the mud and muck of the world into dust and sand, and that she will be
It is also said, in strangled whispers in gloomy corners that she was the first of the Demons, that all others sprouted from her fruits and roots, that the earth about her is scattered with corpses of demons who could not survive their ante-natal plummets. That the Seed of the End of the World was planted when the first murder was born, as flint dug deep into the skull of a friend, where the first scraps of brain matter ever spilled from malice fell.
Other tales tell of how her branches actually reach upwards to try and throttle the sun; how every wicked soul claimed by demons is brought to her to nourish her roots; how it was really the first women scorned by men that fled the world of mortals and forsook her flesh to become the Demon-Tree and that is why it is a she; but these are all tales. None have been to Hell and returned to find out, and presumably if they had, how could a tree speak, and why say any of these things? All these can be nothing more than rumour.