Under the Knife
Location: Abyss / Layer 8—Skindjur
Out on the broken glass plains of Skindjur, there is a weird fortress known as Under the Knife. Looking more like a mutated tree than a fortress, it’s not clear whether the place was built, grown or imagined in a fever dream. The place is psychic crucible where is minds rather than skins that are flayed. Unlike the bloodied machinery of the Tannery or the surgical blades of Beauty is Only Skin Deep, the tools of Under the Knife are invisible—they cut far deeper than flesh, far down into the mind—carving thought, memory, and will. This is a place of psychic surgery, where perceptions are sharpened, knowledge reshaped, and memories destroyed, all with sinister precision.
The town’s ruler is an ancient illithid, a being whose expertise in the art of mental dissection has made Under the Knife a place of great utility for those who deal in power and influence—tanar’ri, factions, and planewalkers alike. Its true master, however, is not the mind flayer itself but something far worse: The remnants of an Elder Brain, a composite-being whose cold intellect has been forever warped by the chaos and cruelty of the Abyss.
The Neurotic Heart
The way in to Under the Knife through a massive crystalline tower called the Shardspire that juts up like a razor-edged claw from the Cauterising Plain. Its structure is unnervingly beautiful and alien, built entirely from shards of transparent crystal flecked with veins of pulsing black and purple light. The tower seems to hum faintly with psychic energy, a sound that gnaws at the edges of thought without ever quite reaching the ear.
The Shardspire is built to disorient. Inside there are no steps or ladders, a body simply wills themselves to rise and they float upwards. It’s the same process to get down. Its walls reflect light, creating a view that seems to stretch into infinity, with countless duplicates of the viewer, each one more out of phase than the next.
The top of the tower is called the Encephalon, and if you found the Shardspire disorientating then prepare to have your mind boggled, cutter. It is a maze of halls and rooms shaped like spherical bubbles, connected by glass corridors, all made from the same reflective crystal. However, rather than reflecting light, the walls here reflect thought. There’s a constant mental chatter here as every body is able to hear the surface thoughts of every other body. It’s deeply confusing, and the babble makes it difficult for the untrained cutter to think clearly. The ‘windows’ show impossible scenes, of memories that are not your own. Visitors often feel as though they are being watched by their own reflection, and many find themselves revisiting old traumas or buried fears as they explore the fortress.
Strapped to the exterior of the spire are countless psychic antennae, spiralling crystalline structures that pulse with stolen thoughts. These devices extend the fortress’s influence beyond the tower itself, drawing in the mental echoes of beings from all across Skindjur, like flies in a spider’s web.
What Happens Here?
Under the Knife exists for one purpose: The cutting and reconstruction of minds. Painful, precise, and utterly violating, the psychic surgeries performed here are sought out by those who believe their ambitions outweigh the cost of such a procedure—or by those who have been dragged here against their will.
The illithids offer services unique to this burg, though they often come at a terrible price. These include:
Memory Flaying: Entire memories can be scraped away, leaving the subject either blissfully ignorant or terrifyingly hollow—depending on the price paid. Some clients pay to forget their greatest failures, while others beg for the memory of old traumas to be excised. Secretly, the removed memories are kept, processed, and sold as commodities. This service is usually performed by illithid lackeys rather than the Surgeon-Primarch itself.
Mindsculpting: The psychic surgeons can “improve” a mind by reshaping its thoughts, sharpening its focus, and erasing hesitation. Many clients seek this service to gain an edge in political dealings or combat situations. The benefits are as promised, but in most cases, any improvements come with hidden scars—concepts stolen, emotions or reflexes dulled, or an unshakable sense of someone else’s shadow in the recesses of their mind. [In game terms, mindsculpting is able to increase a characters Int, Wis or Cha ability scores by 1d2 points, at the cost of 1d3 points of another ability score, as determined by the DM.]
Ego Splintering: Tanar’ri generals or yugoloth elites sometimes come to Under the Knife to “split” their own minds, creating secondary personalities or fragments that can act as independent entities. These splinters are weapons, confidants, or infiltrators—but some break free, becoming nightmares of fragmented thought. This process is highly unadvised for mortals, almost always ending in barminess.
Soul Peeling: The darkest surgeries dig beyond the conscious mind and into the soul itself. The illithid promise to “remove unnecessary weight,” but the results leave subjects feeling hollow and raw, their essence reduced to something fragile and incomplete. This procedure is supposed to ensure a cutter becomes a more powerful petitioner after their death, but the evidence supporting this claim is thin. [In game terms, soul peeling is able to change the alignment of a being, although it will probably feel soulless and empty afterwards].
Why Come to Under the Knife?
Despite its horrors, Under the Knife attracts visitors from all over the planes:
- Ambitious Planners: Tanar’ri generals, yugoloth tacticians, and mortal warlocks seek the surgeries of Qalithrix to sharpen their minds, erase their doubts, or create psychic weapons.
- Desperate Berks: Broken souls come here hoping to have old traumas erased, only to leave more damaged—or never leave at all.
- Collectors of Thought: Waste from Under the Knife takes the form of discarded memories, bottled psychic fragments, and splintered egos, all of which are sold to scholars of secrets, necromancers and witches, night hags, and sadistic Senates.
Who Rules
Presiding over Under the Knife is Surgeon-Primarch Qalithrix (planar illithid [it/its] / NE), an ancient and profoundly twisted illithid whose mastery of psychic dissection is unmatched. Qalithrix is no ordinary mind flayer—it claims to have transcended the limits of its kind through countless surgeries, removing what it calls “the inefficiencies of ego” and reshaping its psyche over centuries of self-experimentation. Whether this is true or a delusion born of its warped mind, none can say, but the result is chilling.
Qalithrix’s form is distinctly wrong, even for an illithid. Its body is unnaturally tall, and its head, crowned with tentacles, gleams like smooth glass, its face reflecting back distorted, agonized versions of all who gaze upon it. Beneath its robes, however, its body appears to be a mass of writing tentacles, rather than arms or legs. Crystals are embedded in its flesh, forming a lattice of psychic amplifiers that thrum with raw mental power.
The Surgeon-Primarch speaks with calm precision, its voice projected directly into your mind, giving a feeling like the scrape of a scalpel over bone. It views all beings as flawed experiments, riddled with weaknesses that only its craft can remove. Qalithrix rarely shows emotion, save for a faint, unsettling satisfaction when speaking of the “untapped potential” hidden in the minds it flays.
Despite its chilling demeanour, Qalithrix is fiercely protective of its domain and its work. It believes that Under the Knife represents the pinnacle of psychic advancement—the perfect synthesis of logic and chaos, an art form born of the Abyss’s cruelty and the mind flayers’ cold precision.
But Qalithrix is not the true master of Under the Knife.
Who Really Rules
Secreted somewhere in the labyrinthine passages of Encephalon lies the Wailing Brain, a corrupted Elder Brain that has practically become one with the Abyss. Once a paragon of logical—if cruel, untouchable intellect, the Wailing Brain was dragged into Skindjur long ago—perhaps by Qalithrix itself. Here, immersed in chaos, it has become a thing of terrible paradox: a creature of cold logic, now driven by madness and cruelty.
The Wailing Brain is a grotesque hybrid of illithid intellect and Abyssal hunger. Its massive, pulsating form is housed in a huge, crystal-lined chamber. Veins of black fluid run through its once-pristine surface, pulsing with chaotic energy that flickers unpredictably. Its psychic presence is overwhelming—a cacophony of screams, whispers, and fragmented thoughts that drives weaker beings to madness.
The Wailing Brain is a being of cold ambition, ruthless and calculating even in its corrupted state. While it allows Qalithrix to rule in appearance, it constantly manipulates the illithid and the burg itself for its own ends. The Brain feeds not only on the psychic energy harvested from surgeries but also on the anguish and despair of those subjected to procedures.
The true tragedy of the Wailing Brain is its awareness. It remembers the unity of its kind, and it hates. It hates the tanar’ri who mock its precision. It hates the chaos that has infected its once-perfect consciousness. And most of all, it hates those who fail to recognise its brilliance.
The Wailing Brain’s ultimate goal is liberation. It yearns to escape Skindjur, and become something beyond Elder Brain—a god of sharp intellect and raw psychic power. Qalithrix remains unaware of its master’s true plans. While the mind flayer believes it controls the Brain, the Brain is slowly reshaping Qalithrix, planting thoughts, doubts, and ambitions in its surgeon’s mind. In time, it may convince Qalithrix to open a planar rift, one that will not only release Under the Knife’s horrors but also unleash the Wailing Brain’s madness upon the multiverse.
Source: Jon Winter-Holt