GM's Glossary: Part 1 - Everything you can do with a Health Bar
This is part 1 of a multi-part series I'm calling the GM's Glossary.
It's going to be a compilation of every status effect and ability you can throw at or on a character to make them a little more interesting. I'm looking to make something that's not exactly system-neutral but that should provide a lot for any OSR designer and should offer something for any other kind of game designer.
The bulk of it's going to be a big list of system neutral status effects but today we're just going to see what we can do by just messing around with health bars. Let’s keep it barebones and assume:
Characters have HP up to their Max HP
Characters die when they hit 0 HP.
HP can be removed with Damage and restored with Healing. I’ll be bundling this together as Effects for convenience.
There’s no range or positioning to consider yet, all combat is taking place in a spaceless void, like a classic RPG encounter:
Here’s just about everything we can do to mess with those:
Buffing / Debuffing
Attacks do more or less damage.
This can also apply to healing.
These could be implemented in two ways, it could modify attacks by a X% or it could give a flat modifier to every instance of damage. In the latter case lots of small attacks would hit differently to one big attack of the same damage.
Resistance / Vulnerability
Character receives more or less damage
This too can apply to healing.
Not all that different from buffing / debuffing the attacker unless we take multiple characters into account. If a party of weak characters are fighting a single strong character, then, all else being equal, it’s better for them to make the strong character vulnerable than it is to buff one of their own.
Critical Hit / Critical Fail
Rare chance of an attack being extra effective or detrimental.
This is a bit system dependent and basically just a variety of buffing/debuffing but it’s common enough that I thought I’d include it for completeness.
This usually means extra damage but it could be any kind of effect.
e.g : A critical hit with a hammer also knocks the target down.
Hit-Chance / Dodge-Chance
Probability of an attack hitting.
Separated into two effects to represent the attacker and defender’s perspective but essentially measuring the same thing.
This is also a bit system dependent, some games like Into the Odd have all attacks hit automatically and skip straight to damage.
While I say ‘dodge’ here this could also represent armor as it does in D&D.
Invulnerability / Incurability
Character can’t be damaged / healed.
Also known as immunity or invincibility.
Invulnerability is usually subject to some condition.
e.g. it only lasts X rounds or it stops when you destroy the dragon’s immortality crystal.
It could also be conditional to certain damage types: ie: the magma worm is invulnerable but only to fire. Damage types are best left for another discussion.
Damage Negation
Completely negates a single instance of damage.
Like a single-use instance of invulnerability.
This can completely shut down a big attack if you can avoid it being wasted on protecting you from a small weak attack.
You could also reverse this to healing negation.
Damage Over Time (DOT)
Deals damage at regular intervals, such as every combat turn.
Commonly used to represent poison, fire, acid, bleeding wounds.
Could contain a stacking effect with repeated use.
Multi-Target
Attack hits multiple targets.
Much to discuss here but I’ll elaborate on this a bit more when we discuss AOE in the next post.
Splittable
Effect can be divided among multiple targets.
Different from multi-target. You’re dividing this damage between targets not hitting all of them with the same damage.
Handy for dealing with multiple low HP enemies.
Magic missiles are the classic example of this.
Consider: an ability that lets you do this to enemy attacks and divide lethal damage among many allies.
Reversal: Mergeable attacks, everyone deals damage at once to overcome armor/resistance/regeneration.
Progressive Modifiers
Damage / Healing increases over time.
Imagine an attack that starts weak but gains in power every time it's used.
This increase could be linear or exponential.
This encourages a character to commit to repeating this action over the course of many turns.
This can be capped or reset if an infinitely scaling attack is game breaking.
This can also be reversed into a strong effect that grows weaker with continual use.
Delay
Effect occurs after a set amount of time.
Usually a price paid for a powerful effect.
If the effect requires continuous effort to charge I’m terming that a windup.
Uses: Slow working venoms, charging superweapons, carefully planned strikes.
Cooldown
After using this ability the character must spend some time recovering.
The reverse of a delay.
Good for lethal but heavily telegraphed moves.
Pretty much like a cooldown but before rather than after an attack.
I’m more fond of using this for enemies since it gives players time to respond.
Sacrifice
Action costs HP to use.
Used for reckless attacks, throwing yourself into danger or good old blood magic.
Drain / Donate
Transfers HP from one target to another.
Draining HP is a great mechanic for Vampires and other life-suckers.
Likewise Donate is a great mechanic for self-sacrificing healers.
Also consider some sort of blood-mage moving HP from target to target.
Healing Reversal:
Character is damaged by healing or healed by damage.
I fucking love when a game implements this mechanic and I can’t explain why.
Overheal
Character gains HP beyond their Max HP.
Also known as temporary hit points.
I suppose you could also do a reversal on this and make temporary damage. Like damage that heals itself over time or that will only kill you if it makes you drop below 0 in the next few turns.
HP Limits
Modifies Max HP
This is assuming any Max HP changes are temporary otherwise this is just your new Max HP.
You could also rule this as a decrease in a character’s minimum HP. This is effectively the same thing but it can be thematically fun for a character to keep fighting at -10 HP rather than just having +10 HP.
Another rephrasing of this is as an increase to a character’s Minimum HP. So instead of dying at 0HP they die at 10 HP.
This is a lot like dealing 10 damage only they can’t heal their way out of it.
Carryover
Damage greater than what was needed to bring a character to 0 HP is dealt to another target.
Good for representing weapons that cleave and pierce through their targets.
This might also be redirected at the attacker to represent their overuse of force hurting them.
Retargeting
Changes the target of an attack.
Uses: Grabbing an enemy (or ally) and using them as a shield, the D&D monk’s deflect missile ability, throwing yourself in front of an attack.
Transfer
One character receives an effect directed at another.
Similar to retargeting but this assumes the attack actually hits the original target but the effect is transferred over to the new target.
Uses: Sympathetic spell transferring a wizard’s wounds to a tank. Vulnerable voodoo doll taking damage and directing it at an armored enemy. Regenerating meat-god absorbing healing magic for itself.
Bond
Multiple characters are linked. Effects applied to one are applied to the others also.
Like a transfer but the original target still receives the effect.
Bond two enemies to double damage.
Bond two allies to double healing.
Bond an allied tank to an enemy glass cannon.
Reverse: Character A receives the opposite effect of character B. Heals when they take damage, takes damage when they heal.
Resurrection:
Dead character returns to life.
I should note here that 0 HP doesn’t necessarily have to mean death. It could represent incapacitation or just be the beginning of a countdown to true death.
Triggers
Effect is triggered by something happening to a character’s HP
This is a general category that can combine with other effects for interesting mechanics.
I’m bundling this together with Gating, which is when an ability requires something to happen or be a certain way in order to be used.
You can attach a trigger to any of the mechanics we’ve discussed so far but here are some common examples:
Damage / Healing Trigger
Effect triggers when a character is damaged/healed.
e.g: Alien’s acid blood damages nearby characters.
HP Trigger
Effect triggers when a character reaches a certain level of HP:
e.g: Character who is considered maimed at half HP. Bosses that enter a second phase at half HP. Special ability that can only be used on max HP.
Death Trigger
Effect triggers when a character dies.
e.g: Explosive enemy who blows up on death. Items that auto-resurrect you on death, like a zelda fairy.
Kill Trigger
Effect triggers when a character has killed one or more others.
e.g: Demon blade that grows stronger with every kill.
I think that just about cover’s everything. If you can think of more please comment below as long as your suggestion isn’t:
System-specific:
Trading Mana for HP, Recovering injuries.
I’m only looking for generally applicable mechanics.
A combination of other effects:
e.g: Mass healing doesn’t need it’s own category since it’s just a combination of Healing and Multi-Target.
Overly specific:
e.g: Immune to damage if it’s a multiple of five.
Not that I don’t love weird mechanics like this, I just want to create a list that’s generally applicable.
Circular one-upping:
e.g: This enemy is Super-Resistant and can’t be made Vulnerable. But my character can cast Hyper-Vulnerability which overrides everything except Ultra-Resistance…
Just assume that any effect here can be negated and overridden to your heart’s content.
EDIT:
Grek of Grackle Court suggested a few additions. I’ve copied Grek’s original message into the comments.
Stopping Points
Damage or Healing can’t move HP past certain points.
This usually comes in form of multiple health bars.
So, for example, my big attack might bring an enemy’s first helath bar to zero but excess damage doesn’t carry over to it’s second health bar.
Likewise the enemy loses their first health bar and can’t heal into it, effectivly a max HP reduction.
Health Bar Types
Characters have multiple health bars that behave differently.
These might represent armor, shields, or flesh.
One might regenerate, another might be resistant or vunerable to different damage types another might be impossible to recover, etc.
Grek's original comment:
For DOT, a fairly standard mechanic in CPRGs is a status that alters its DOT each time it triggers. The usual example is a 'poison' effect that does damage equal to its remaining duration, slowly wearing off in time, but you can have one that gets worse over time or wears off faster. Or a healing effect that works the same way, initially strong but tapering off. In the 'damage equal to remaining duration' case, this has the interesting effect that doing 5 poison = 15 damage over 5 turns, but 5 poison and then 5 poison a turn later is 50 damage over 9 turns.
For Overheal, temporary damage is often used to represent 'illusion' damage that disappears after a particular opponent is defeated. Sometimes too much temp HP (often total HP > 2x Max HP) is also fatal, letting someone 'attack' by healing someone past their max HP.
There's also Multiple Health Bars. In Halo, for example, you have Shields (which recharge over time) and Health (which does not). Attacks damage Shields before Health, but if you ever lose Health, that is effectively lost Max HP. Other times, a character gets trapped in ice and their allies can break them free early by attacking the ice. A third application, often seen on bosses, is to have their Health Bar broken up into segments, such that damage done in one segment doesn't carry over onto the next, but neither does any healing the boss does.
It can also be the case that certain effects behave differently against the two different Health Bars - an EMP that can only harm Shields, or a Transfer effect that can only steal Health, not Shields. Whether damage from one carries over to the next or gets cancelled varies.
For Delay, a common variant is the effect can be cancelled if the user is damaged or killed prior to the effect going off. The latter is practically default, even. Theoretically this could also apply to Cooldown (effect happens immediately, but it can be undone by hitting the person who caused it fast enough.)