Weirder Diseases

Pneumonia, syphilis, mummy rot or the plague are nice and all, but maybe you want some stranger diseases for a change?

d30 Diseases

1. Asonia: You negate sounds. Not only you cannot speak, but you walk, fight or scream in complete silence. You also cannot hear, as the sounds don't reach your inner ear.
   
2. Astral hiccups: Any time you are scared or surprised, you experience an involuntary, uncontrolled teleporation.
3. Biokinetic drift: Your body is not yours. Every day, Save or reroll your race and sex.
4. Bone blight: Bone protrusions pierce your skin from the inside. Loose 1 maximum hp per day, but gain a passive counterattack dealing 1d6 damage from the spikes. Even if the disease is cured, the spikes and hp loss do not go away. Try a biomancer to fix that.
5. Chronal tumour: Whenever you go to sleep, Save or fall into future. First days, then weeks, months or years.
6. Clockwork virus: Loud ticking is heard from your innards instead of heartbeat. Loose 1d4 Constitution and Intelligence per day as you turn into a clockwork automaton. Once you reach 0, there is nothing but your skin left over the cogs, axles and pulleys.
7. Common fire: Where common cold is caused by cold and wet, common fire is caught in hot and dry places. Loose 1d4 Strength per day and cough up smoke.
8. Cooties: You can only infect and be infected by members of the other sex. Loose 1d6 Charisma per day. You become more and more nervous, awkward and incompetent around the other sex.
9. Eyeball cancer: You grow new eyeballs all over your body. One by one, they will detach as floating eyes and fly away. That's how floating eyes reproduce.
10. Enflamed eyes: Anything you leave your eyes on for more than a few seconds will burst into flames.
11. Hecatoncheiritis: Grow one new, fully functional arm per month. Becomes a real problem once you have so many arms you can barely move.
12. Hollowing: You feel empty inside. Your thoughts are slower, emotions dull. Nothing scares or excites you. Loose 1d6 Wisdom per day. Once you reach 0, any damage crumbles you into a pile of grey ash, revealing you were actually hollow inside.
13. Hyperfertility: All of your bodily fluids cause impregnation on skin contact, even in males with 5% chance. If you're female, you can impregnate other females but cannot be self-impregnated.
14. Hypergravity syndrome: Your personal gravity field slowly collapses. It will become harder and harder to move as you weight twice, thrice, five times more than normal. Loose 1d6 Strength per day. Most people are cured or die before they can form a miniature black hole.
15. Lucky death: Four-leaf clover lesions cover your body. You may reroll any roll except Saves against this disease at the cost of 1d6 points from random attribute. If you don't use this ability at least once per day, loose 1 point from every attribute.
16. Magicbane: A spell has died in your brain and now other magic is avoiding its carcass. Effectively you have an antimagic field extending 5' around your body. Don't forget that even things like potions, portals or enchanted prosthetics are suppressed.
17. Massmind malaise: You feel strangely stretched out. Loose 1d6 Intelligence per day and broadcast your every emotion and thought to creatures within 30'.
18. Mortambulism: Your body forgot how to die. You remain aware no matter your injuries, but once damaged beyond your natural healing ability, you cannot be easily put together again. Enjoy eternity in pieces.
19. Phase fever: You flicker in and out of this dimension. Every physical interaction has a chance to fail as you turn intangible at the wrong moment. The chance starts at 1-in-6 and grows as the illness progresses.
20. Phytogenetic disorder: You turn somewhat green. Loose 1d6 Strength every day unless you had at least four hours of sunlight.
21. Psionic self-loathing: Add an evil twin of yourself to the random encounter table. It's a tulpa that you unconsciously create, bent on destroying you and all that you value. Even if killed, it will return again and again until this disease is cured.
22. Psychic seizures: Your soul leaks from your body. Loose 1d4 Intelligence and Wisdom per day. Every time you take damage, all creatures within 10' must Save vs stun as you broadcast the pain.
23. Regressive crystallization: Loose 1d3 Dexterity and Constitution per day as you slowly turn brittle and crystalline. At least you'll leave behind a beautiful statue.
24. Rockefeller's disease: Loose 1d4 Constitution per day. A number of sores on your body steadily seeps with black, highly flammable puss.
25. Rust plague: Your sweat and tears are flakes of rust. Your touch causes rapid rusting. Loose 1d3 Dexterity and Charisma per day.
26. Spontaneous combustion syndrome: This disease lays dormant until the time of death. Then you explode, dealing 3d6 fire damage in 10' radius and infecting everyone burnt with the disease.
27. The drips: Your nose drips with green slime. You are immune to its effects, but your equipment and allies not so much.
28. The shivers: You are bluish in complexion and so cold you are covered in rime. Unless constantly warmed up, you will freeze to death. Loose 1d6 Dexterity and Constitution per day.
29. Throat rot: Your throat is sore and your tongue is covered in putrescent blisters. Loose 1d4 Constitution per day, plus Save or vomit every time you try to eat. If you fail three daily Saves in a row, your tongue rots off completely.
30. Unlight sickness: Light no longer interacts right with your diseased body. You are invisible in direct light and translucent in dim light. Loose 1d4 Charisma per day.

On Madness

Here is my take on the insanity rules. I took inspiration from these posts, so I should give credit where credit's due.

From Darkest Dungeon.

Trauma is gained when you loose limbs, friends, or see what no human should. You might gain more than 1 point at once, depending on the circumstances. Every time you gain any Trauma, roll under [Will  - Trauma] or Crack. Critical failure, gaining Trauma equal to Will, or gaining enough Trauma that your Memory overflows (see below) causes permanent Insanity and resets Trauma back to 0. Rolling exactly the target number instead grants you a random Virtue. Each point of Trauma also fills a Memory slot. Insanity does not go to your Memory, and instead is treated as an injury.

A nightly rest may reduce Trauma by 1 if you get drunk, high, laid, or otherwise relieve stress. A week of recuperation in town removes 1d6+WIL Trauma. Insanity cannot be removed by any normal means, but can be alleviated by various potions and therapies.

The Hunger, the Madness, the Crime

d8 Cracks

1. Abusive: Why aren't they pulling their weight? For 1d6 rounds when an ally fails an action, they take 1 Trauma as you scream obscenities at them.
2. Blackout: You faint for 1d6 rounds. You can be slapped awake.
3. Breakdown: You cannot see for tears, nor speak for sudden stutter. Lasts 1d6 rounds.
4. Fight-or-Flight: For 1d6 rounds, you either viciously attack the source of Trauma, or run away. Your choice.
5. Hopeless: All is lost. Your despair makes all allies roll with disadvantage for the next round.
6. Nausea: You gag or vomit for a round, and cannot benefit from Lunch today.
7. Scream: Aaaaaaaaaaaaaaaa!!!!!!! If anyone didn't know you are here, they will now. May provoke a Random Encounter.
8. Shock: What's happening? Save once per round, until you succeed you can take no actions.

d8 Virtues

1. Confidence: You will prevail. You deal +1 damage until the end of encounter.
2. Courage: There is nothing to fear but fear itself. You are immune to fear and Trauma until the end of encounter.
3. Focused: Suddenly, a moment of inner peace. You have advantage on your next roll.
4. Inspiring: Your unwavering resolve emboldens your allies. They may all roll a new Save against one of their current afflictions.
5. Invincible: You must persevere. You postpone all injuries and madness until the end of encounter.
6. Selfless: You are all in this together. You may redirect an attack from an ally to yourself until the end of encounter.
7. Stalwart: None shall pass. You cannot be moved, knocked prone or tripped until the end of encounter.
8. Vigorous: You feel more alive than ever before. Heal 1d6 hp.

Insanity by kiki71

d20 Insanities

1. Addiction: You need your fix to get through the day. If you don't get your drug, you automatically Crack every time you gain Trauma, in addition to any withdrawal effects.
2. Amnesia: Roll d20 on your Memory and loose whatever is in the slot you rolled. If you roll an empty slot, that slot is permanently filled with Brain Damage.
3. Anxiety: Your are a nervous wreck. You take -4 on Saves vs Fear and all fear effects have double duration for you.
4. Catatonic: You are completely unresponsive until you can be brought back to town and nursed back to your senses over an extended rest.
5. Delusion: Roll d6: 1) You are the long-lost heir of the throne. 2) You can fly*. 3) You will burn in sunlight. 4) You are of a different race / an animal. 5) You are invincible. 6) All magic is inherently bad. You cannot be convinced otherwise and rationalise any evidence as an illusion, trick, or any barely believable "explanation".
6. Depression: Every day is a struggle. Roll with disadvantage until the first time you succeed on a roll in a given day.
7. Hallucinations: The GM might sometimes describe something incorrectly or in a misleading way to you.
8. Insight: When encountering a thing beyond human comprehension, you have a 50% chance of gaining a useful piece of information, and a 50% chance of trying to claw your eyes out, taking 1d6 damage and blinding yourself for 1d6 rounds.
9. Minor Compulsion: Once per day when the GM calls for it, you must stop everything else to satisfy your compulsion (wash your hands, count your money, vandalise something). Good roleplaying of the compulsion should prevent the GM from using this at too troublesome times.
10. Major Compulsion: Once per week when the GM calls for it, you must stop everything else to satisfy your compulsion (kleptomania, necrophilia, cannibalism). Good roleplaying of the compulsion should prevent the GM from using this at too troublesome times.
11. Nightmares: Save each night or wake up screaming, gaining only half the effects of rest. Alcohol or opiates may grant you serene sleep.
12. Obsession: You become obsessed with a random person and start following them around. You "love" them. If you don't see them for a day, you automatically Crack every time you gain Trauma.
13. Paranoia: No one counts as an ally to you. You must Save to accept aid or work in a team.
14. Phobia: You have a phobia based on what caused this insanity (or roll a random one if this does not make sense). Gain 1 Trauma when you encounter something that triggers your phobia.
15. Quirks: You have personality quirks. Severe ones. Roll d8: You 1) talk to yourself, 2) laugh wildly and inappropriately, 3) constantly fidget, 4) eat odd substances, 5) mimic those around you, 6) have irritating tics, 7) stutter, 8) suffer tremors. You take a penalty to Reaction rolls and social checks equal to current Trauma.
16. Sadism: You are brutal and violent. Every time you kill a creature, everyone in sight takes 1 Trauma as you revel in the suffering.
17. Schizophrenia: Make a new character sheet with a different class, but the same name, race, attributes etc. Each session, alternate between these two character sheets.
18. Self-Mutilation: Every time you would take Trauma, you can instead take 1d6 damage. If you take no damage for a whole day, you must hurt yourself for 1d6 damage. You are covered in scars.
19. Submission: You are seriously aroused by being ordered around. You must Save not to follow a command and may want to seek out someone who will abuse you and treat you like their slave.
20. Veracity: Every time you deliberately lie, Save or faint.

*) If you actually can, then you believe you cannot.

Levels, Hit Points and Willpower

I dislike the way d20 systems tend to give you free hp bonus as you level up. While GLOG does away with the hp bloat the plagues other systems, you still gain hp with level ups. Yes, you are learning, getting more experienced and better. But that's why you gain new abilities with levels, so why would you also get harder and harder to put down in combat when your area of expertise is elsewhere? Fighting classes, who are most definitely justified in getting tougher with experience, already get class-based hp bonuses, so why retain the automatic increase for everyone?

Therefore, your hit points no longer increase from levelling. You have maximum hp equal to your Constitution, plus any class bonuses and such. That makes low Con character very fragile, but then that's to be expected and they can try playing in a way that does not put them in the harm's way.

In the same way as "don't get hit" points are a measure of how well you can take physical punishment without injury, I'd like to have an abstraction of mental health / stress resistance / sanity. This will be your willpower (wp) and will work in pretty much the same way as hp. You will have maximum wp equal to your Wisdom, plus any class bonuses and such.

In addition to psychic damage, I'm thinking about making fear, charm and similar mind-affecting effects deal damage to your wp, straining your psyche until you snap at 0 wp. Rules for stress from dungeon crawling, horror of meeting monsters, madness, insanity and nervous breakdowns will also be required. :)