Your body is not a single solitary thing. It is a temporary confluence of trillions of cells depending on each other for mutual survival. Sometimes a cell doesn't behave in the interest of the unified whole. It takes more than what was allotted to it, refuses to expire when its time comes.
As with the body, so with the soul. The spirit and flesh alike can become cancerous.
(These souls in particular:)
Your mineral soul is responsible for maintaining your form, and facilitating material interactions. Even rocks have mineral souls. A functional mineral soul is humble and fundamental.
A cancerous mineral soul is a usurper.
It infiltrates upwards. You'll start getting cravings, for clay, for eggshells, for razor blades. Movement becomes agonizing as bones expand outwards in spines and spurs and flesh is replaced with brittler tissues.
When it reaches the parts of your mind your thinking will become dull and rote. You'll narrow your focus from the lofty to the day-to-day, then moment-to-moment, from the difficult or artistic to the concrete and straightforward.
When the mineral soul (which by now is most of you) collides with something you can no longer understand it subducts that thing, lashing out to drive it down into something it can. Break down, compartmentalize, regulate, standardize.
All this time you've been growing bigger and tougher, better able to subduct the world into your pinprick vision. You still hurt, you always hurt, but you can't be harmed like you used to. Pain is just another input.
As the mineral soul is the most fundamental of the souls, cancer of the mineral soul is the most difficult to treat. The only treatment is to transfer the higher souls together into a new vessel. More commonly the calcified giants afflicted by it will be killed, or driven out into a wasteland where it is simpler and more comfortable for them.
There are certain crystalline elements that are repugnant to the earth. Their origin is the horrid fusion of contrasequential stars. Like a body forms a cyst to protect itself from contamination, the earth will sequester these elements in geodes. Exposure to these elements, most often through mining for precious gems, is the main cause of cancer of the mineral soul.
Your vegetable soul is your biology, more or less.
A cancerous vegetable soul oversteps its bounds. Are the clothes you're wearing or the chair you're sitting on part of your body? A cancerous vegetable soul would certainly think so, and thread them with the veins and skin they're bizarrely missing, maybe add some eyes for good measure.
Biologic will also be applied to your other souls. Your most deeply held beliefs? Been around too long, gotta undergo apoptosis. Only got the one personality? Needs redundancy. Develop three more. Other people become like alien limbs, appendages that must be cured of their rebelliousness.
You will also get a lot of regular cancer.
Cancer of the vegetable soul is treatable with careful proportions of poison, so careful only a master assassin would be able to mix them. Its predominant cause is healing magic.
The animal soul governs instinct. One would be wrong to assume it's a base and simple thing. It's sophisticated and multifaceted well beyond the design of the fumbling conscious mind.
Cancer of the animal soul is isolated to only one of its facets, an artifact of one of its defensive mechanisms. This might be any of fight, flee, freeze, fuck, eat, sleep, protect your family, and so on. An afflicted facet becomes an obsession. The obsession becomes essence.
The animal soul will bully and subordinate the other souls to its solitary end. The body will be made to mutate, adapt, specialize, as evolution magnified into a single lifetime. Someone with cancer in their 'fight' instinct might grow fractally sharp claws, the ability to read another's every intention in a muscle twitch, denser muscles and bones, or ten thousand other abilities piled on. Bits and pieces like compassion and vocal cords become sacrificed for efficiency. You, or at least the part of you you typically think of you, will be a passenger in your own flesh, able to offer direction only so far as it lines up with where the animal soul wanted to go anyways.
The less said about what happens when the mating facet takes over the better.
The animal soul tends to become cancerous when you lean too far towards either extreme of indulgence or repression. It's found equally in bohemians and nuns. There is a heavily illegal aphrodisiac which can also induce it.
Treatment involves hypnosis, guided psychedelics, and occult surgery. The cancerous facet is tempered and sealed away. Balance must be reached with the beast. Also you can do a Cronenburg-werewolf thing when your equilibrium slips.
The purple soul contains memory. Of all the higher souls it exhibits perhaps the most taxonomic variation: crystal clear to murky, drifting or fixated, bright or bleak, to say nothing of the contents and their voluminous deformations.
Cancer of the purple soul is among the most common of spiritual afflictions, and typically benign. If you find yourself dwelling in the past to the detriment of more lively pursuits then you might have it.
It's when you withdraw from what is and will come, lose connection to the present, are passed by and left behind that cancer of the purple soul metastasizes and becomes a danger to yourself and everyone around you.
Since the purple soul is closest of the chromatic souls to the lower souls, it's in those that the symptoms first surface. Aging slows and arrests, and so does healing. Scars open again, and weep. Your hair falls out, then your nails, then your teeth.
You become able to only live in the past, in a literal sense. Your life up til then is your range of motion. Do you remember the way you die? No? Then don't worry. None of this can kill you.
Your memories will churn and condense. You'll spend more time in flashbacks than in the moment. Pressure will build. When it gets to be too much for your body to hold it'll all pop out your blue soul like uncorked champagne.
At the core of a confabulatory labyrinth built from the bricks of your history you'll regress to your very first memory, into warm darkness. Safe and sound, ignorant and impotent.
Treating cancer of the purple soul is preferably a matter of prevention. Don't let yourself or those close to you lose touch. Limited success has been had after metastasizing with high amnesiac doses, and targeted brain trauma.
The red soul determines your personality: mannerisms, moods, perspective, style.
Imagine standing between two funhouse mirrors. That's kind of what cancer of the red soul is like.
It amplifies and caricatures who you are and how you do what you do, and at the same time makes you hyper-aware of every aspect of yourself. What came naturally becomes a performance, what feels like the most important performance of your life. You have to be a certain way, you have to have other people believe without a doubt that that's who you are. Morality is irrelevant next to your aesthetic.
Even without the spiritual cancer, people can sense other peoples' red souls more than any other sort. The cancer builds on that, gives you a terrifying charisma that makes your audience ignore the warning signs as they're dragged into your orbit.
After your red soul's taken over, your body becomes as fragile as your sense of self. An injury to either causes the other to rupture and spill ichor the colour of good wine. Imbibing it infects the drinker with your tics, prejudices, and fashions. At this point you're nothing but a weak vessel to your red soul. It seeks to transcend you. When it does you'll be a boring shell, and it'll be a psychic plague.
Cancer of the red soul is most effectively treated in the early stages by consuming gruel and otherwise immersing victims in blandness. In later stages the recommended treatment is assimilation into a group identity that surpasses the victim's own, though beware of egregores.
The white soul is responsible for intellect, and for desires.
Cancer of the white soul is one of the few diseases that can be accurately diagnosed through phrenology. When you've got it your skull will fracture and expand. Throbbing veins will crawl across it. Skin between cracks will stretch to translucency and display the wriggling brain matter beneath it.
With the disease comes genius. Learning quickens until it's lightning-fast. Previously intractable problems become as easy as tic-tac-toe.
With the genius comes megalomania. You don't want more, but you want bigger. If before you wanted a royal commission, after you'll want to be king. If before you wanted to settle down with a happy family on a farm, after you'll want the happiest family, the best possible farm. Your desire will grow faster than your means to achieve it. Hubris is inevitable.
By the time you reach that point you'll be unable to accept it. You'll prefer to destroy everything rather than have your ambition denied. If allowed to run its course, every case of cancer of the white soul ends with the construction of a doomsday device.
Sudden revelations and eureka moments are a risk factor for developing white soul cancer. Certain heterodox theories can be memetic vectors. Primitive battery-like devices have been discovered in ruins of the [REDACTED] culture which generate "empyrean lighting" that causes white soul cancer 9 times out of 10.
Sensory deprivation, head binding, and lead have all been believed to cure white soul cancer at one point or another.
The blue soul connects the rest to the divine. When it becomes cancerous that connection becomes circular, a self-consuming and -sustaining ouroboros. The All is caged in the One.
In other words, cancer of the blue soul is godhood. Its causes are sealed under pain of eternal damnation.