Conditions alter a creature’s capabilities in a variety of ways and can arise as a result of a spell, a class feature, a monster’s attack, or other effect. Most conditions, such as blinded, are impairments, but a few, such as invisible, can be advantageous. A condition lasts either until it is countered (the prone condition is countered by standing up, for example) or for a duration specified by the effect that imposed the condition. If multiple effects impose the same condition on a creature, each instance of the condition has its own duration, but the condition’s effects don’t get worse. A creature either has a condition or doesn’t. The following definitions specify what happens to a creature while it is subjected to a condition.

The character’s thinking is damaged by drink, disease, magic, or brain trauma. The character has disadvantage on any Intelligence checks including Arcane magic spell checks. Addled spellcasters may not cast or maintain spells or effects that require concentration.

The character’s arm is severed, crushed, or rendered useless. The character cannot climb, use shields, dual wield, or use two-handed weapons. If the character loses use of both arms, they are paraplegic. They cannot climb, use weapons or items, open locks, remove traps, or any other similar actions.

Any character that is asleep is considered to be unconscious.

A blinded creature can’t see and automatically fails any ability check that requires sight. Attack rolls against the creature have advantage, and the creature's attack rolls have disadvantage.

Once a creature has lost half or more of its maximum hit points, it is considered bloodied. Being bloodied can trigger certain actions specified in the monster or talent description.

A charmed creature can’t attack the charmer or target the charmer with harmful abilities or magical effects. The charmer has advantage on any ability check to interact socially with the creature.

A confused character acts randomly. At the beginning of each round, 2d6 is rolled. The table below determines the character’s behavior for that round. Die Roll (2d6)

Confused spellcasters lose concentration.

A cursed character finds they have awful luck doing things. They make all skill checks and attack rolls at disadvantage, and any roll of a 1-3 acts as a critical failure. A curse might last for one round to a lifetime, but typically this condition only lasts for the duration of one fight.

A deafened creature can’t hear and automatically fails any ability check that requires hearing.

A creature that has fallen into pessimism due to mistreatment or stress roll morale checks at disadvantage and any of their critical successes are treated as normal rolls.

A disfigured character’s body has been twisted and broken from wounds or magic. They move 10’ slower than they should, may not forced march, and suffer a -1 AC penalty from their halting gait.

Disoriented creatures receive a -2 penalty to all checks and attack rolls. Unless mentioned otherwise, this effect lasts one round. Disoriented spellcasters must make a check to maintain concentration.

Creatures distracted by nagging stress take a -2 penalty to armor class.

Your lips and tongue are severed, mangled, or rendered inoperable. The victim cannot effectively speak, cast spells or use magic items involving speech, and they suffer a disadvantage to morale and reaction rolls.

The character is under the control of another creature. It obeys the dominator unfailingly but suffers a -1 penalty to all rolls. Unless dominated for a prolonged period of time, the master creature will most likely not know about the dominated being’s special abilities, like spellcasting. Dominated characters may continue to concentrate on spells and effects or dismiss them at the whim of the controlling creature.

A drained character suffers a -1 penalty to all checks and attacks. A character can be drained several times, each time increasing the penalty to checks and attacks. The duration could be anywhere from one round to permanent. Unless mentioned otherwise, this effect lasts for one minute or one fight whichever is longer.

A character that loses an eye or sight in one eye is Enucleated. A character with this condition suffers a -2 penalty to any missile attacks they make. A character that has this condition, and suffers this same condition again is instead blinded as they lose their other eye.

Items and weight are tracked in terms of load. Each item the size of a human head or 5 lbs is considered 1 load. PCs are able to carry load equal to their Strength score without issue. A character carrying a load over their Strength score causes them to be encumbered.

Encumbered characters reduce their speed by 5’ every point of load over their Strength, and forces disadvantage on all checks.

When a character is entangled, he moves at half speed and loses his Dexterity bonus to armor class. Entangled characters that try to cast a spell have to make a concentration check or the spell is lost.

An exhausted character has one or more levels of exhaustion.

A fascinated character is entranced by an effect, often a supernatural one. He will not act as long as the effect lasts. If he is threatened, the character is permitted an appropriate check to break free. A fascinated spellcaster automatically loses any spells or effects that require concentration.

A frightened creature has disadvantage on ability checks and attack rolls while the source of its fear is within line of sight. The creature can’t willingly move closer to the source of its fear. A frightened spellcaster must make a concentration check or lose any spells or effects that require concentration.

A grappled creature’s speed becomes 0, and it can’t benefit from any bonus to its speed. The condition ends if the Grappler is incapacitated (see the condition). The condition also ends if an effect removes the grappled creature from the reach of the Grappler or Grappling effect, such as when a creature is hurled away by an effect or spell.

A creature filled with dread or suffering from stress may take their Active action or Quick action each round, but not both.

An incapacitated creature can’t take any actions. They immediately lose any spells or effects that require concentration.

An invisible creature is impossible to see without the aid of magic or a special sense. For the purpose of Hiding, the creature is heavily obscured. The creature’s location can be detected by any noise it makes or any tracks it leaves. Attack rolls against the creature have disadvantage, and the creature’s Attack rolls have advantage.

Lame characters may only move at half their maximum speed and they lose all Dexterity bonuses to armor class.

A maimed character may not use a hand due to it being severed or crushed, or being rendered useless by magic. They cannot dual wield or use two-handed weapons.

The character has been gruesomely scarred. It is impossible for them to impersonate another. While they gain +2 to intimidate others, they suffer a disadvantage to any other Charisma based checks or skill checks.

A creature pained by injury or internal injury or perhaps suffering headaches from stress may not add their proficiency bonus to any skill checks.

A paralyzed creature is incapacitated (see the condition) and can’t move or speak. The creature automatically fails Strength and Dexterity Saving Throws. Attack rolls against the creature have advantage. Any Attack that hits the creature is a critical hit if the attacker is within 5 feet of the creature.

A petrified creature is transformed, along with any nonmagical object it is wearing or carrying, into a solid inanimate substance (usually stone). Its weight increases by a factor of ten, and it ceases aging. The creature is incapacitated (see the condition), can’t move or speak, and is unaware of its surroundings. Attack rolls against the creature have advantage. The creature automatically fails Strength and Dexterity Saving Throws. The creature has Resistance to all damage. The creature is immune to poison and disease, although a poison or disease already in its system is suspended, not neutralized. Petrified spellcasters lose any spells or effects that require concentration.

A poisoned creature has disadvantage on Attack rolls and Ability Checks.

A prone creature’s only Movement option is to crawl, unless it stands up and thereby ends the condition. The creature has disadvantage on Attack rolls. An Attack roll against the creature has advantage if the attacker is within 5 feet of the creature. Otherwise, the Attack roll has disadvantage.

A restrained creature’s speed becomes 0, and it can’t benefit from any bonus to its speed. Attack rolls against the creature have advantage, and the creature’s Attack rolls have disadvantage. The creature has disadvantage on Dexterity checks.

The creature has failed a morale check. It must flee at maximum speed away from the battle, by the safest possible route. If unable to escape, the creature becomes Frightened.

The character is severely scarred. The character is -2 to throws to impersonate another person. Three scars will make the character mauled.

Shaken characters are afraid of something, but still in the fight. They suffer disadvantage on further morale checks and they can’t willingly move closer to the source of their fear. Shaken characters who fail their next morale roll are immediately Frightened.

A slowed creature moves at half speed. It takes a -2 penalty to AC and Dexterity based checks, and it can't use Quick actions. Regardless of the creature's abilities or magic items, it can't make more than one attack of any type during the round. Unless mentioned otherwise, this effect lasts one round.

The character can only use their Active action, losing both their Move and Quick actions in the round. Unless mentioned otherwise, this effect lasts one round. Spellcasters who are Staggered must make a check to maintain concentration on a spell or effect.

A stressed character has one or more levels of stress.

A stunned creature is incapacitated (see the condition), can’t move, and can speak only falteringly. The creature automatically fails Strength and Dexterity Saving Throws. Attack rolls against the creature have advantage. Unless mentioned otherwise, this effect lasts one round. Spellcasters who are Stunned must make a check to maintain concentration on a spell or effect.

An unconscious creature is incapacitated (see the condition), can’t move or speak, and is unaware of its surroundings. The creature drops whatever it’s holding and falls prone. The creature automatically fails Strength and Dexterity checks. Attack rolls against the creature have advantage. Any Attack that hits the creature is a critical hit if the attacker is within 5 feet of the creature.

I'm going to add some particular conditions to reflect maimings from going to zero hit points, as well as conditions for new spells.

I've cleaned this up. Now I just need to connect the maimings to the appropriate tables and add the effects to the appropriate spells. I've added a few new conditions that are re-used a lot such as Confusion and Slowed, as well as a few cases that aren't as awful as Stunned or Paralyzed for lower level play which could be useful when making monsters.

Dread - May take their Active action or Quick action each round, but not both. Headaches - Proficiency bonus not added to checks. Pessimism - Critical successes are treated as normal rolls.