Comparison: Calculating Melee Defensive Capabilities in different RPGs

This is a continuation on the theme of a previous post. The theme of this post will be calculating defensive capabilities. Specifically, in terms of the pre-battle calculations that generally do not need to be run at once. As before, the systems in question are GURPS (of course), D&D, Fate, Savage Worlds, and Ryuutama.

GURPS

Hit Points

A common mechanic in many RPGs, GURPS also uses hit points (HP). HP can have different meanings in different systems depending on the context, so just to be clear, in GURPS, HP is your
"meat" points, and losing them means you are being wounded. In GURPS, HP are tied to the strength attribute (ST) and go up as ST goes up, or can be improved by themselves at a discounted rate. HP recover pretty slowly in comparison to other systems, but this makes more sense when HP loss literally translates to wounding and damage rather than other more nebulous concepts. Because of this, typical players in GURPS have less HP than in other systems.

Active Defenses

All melee damage in GURPS can be negated by an "Active Defense". The vast majority of characters have a "Dodge", a large majority have a "Parry", and those that have a shield have a "Block". Dodge is calculated differently, but Parry and Block are almost the same (so much so, that some fans say that they should actually have the same name to simplify mechanics a bit further, but, eh.) 

Dodge is calculated as Speed + 3. Speed is calculated as (HT+DX/4). Dodge is rounded down to the nearest integer (in GURPS, Speed is not an integer; the one important "secondary characteristic" that is not.) It is also penalized by a gradient encumbrance scale, with 0 penalty at no encumbrance, and a maximum possible penalty of -4 for "X-Heavy" encumbrance, which is usually measured in many hundreds of pounds. A character may dodge many times in one turn.

Parry and Block are calculated by taking the weapon (for parry) or shield (for block) skill dividing by 2, and adding 3. Shields usually have a special bonus applied, "Defense Bonus" (DB) which adds to all active defenses, increasing dodges, parries, and blocks. It is cheaper by more than half in regular circumstances to increase block or parry by one point than to increase dodge by one point and they are (normally) not impacted by encumbrance, but in the simplest form of the GURPS combat rules, a character can block or parry only once each in a given turn.

Damage Resistance

An attack that is not successfully defended against incurs damage on a target. The final line of defense is armor which grants "Damage Resistance" (DR) DR simply subtracts from the total damage received in the simplest cases. That is, if an attack were to do 5 damage, and one were wearing armor DR3, the attack would inflict a 5 - 3 = 2 wound. Damage Resistance is normally increased via buying more expensive armor; this conflicts with encumbrance however which will penalize the ability to dodge.

Health

The last line of defense to a heavily wounded character in GURPS is the "Health" (HT) stat, which determines, when a character is at negative health, how likely they are to fall unconscious, or worse, die. Each level of HT directly increases the odds of remaining standing at negative health.
In Summary:

• HP is short hand for how close someone is to dying, and is based on ST in most cases.
• GURPS has 3 active defenses that allow a character to avoid 100% of melee damage. These three defenses have two distinct formulas that are full of seemingly arbitrary numbers, but short enough to write down until memorized.
• If hit, DR normally acts as a flat reduction to damage. DR is simple to improve and normally only requires finding a place to buy armor.
• The Attribute Health, HT, directly impacts survivability, and each level increases the odds of continuing to remain conscious or alive.

D&D 5e7

Hit Points

Again, this system uses the concept of Hit Points, but Hit Points are a bigger abstraction than in GURPS. HP represents exhaustion and grit and stick-to-it-ivity in D&D, so losing HP isn't saying that you were literally stabbed; it could mean cumulative stress from repeated near misses, blunt trauma from being beaten on, or just exhaustion from fighting too long. In turn, recovering HP is also much easier as would make sense, and even mundane means of recovery quickly restore many HP. HP go up a certain amount each level based on hit dice; Hit Dice are calculated via a lookup table for Constitution's modifier and a specific die for the character's class. Both require fiddly lookup tables, but not very often.

Armor Class

Armor class (AC) is an abstraction of many concepts, and represents the abstract quality of being able to resist losing HP, which is also an abstract metric. High AC could mean being able to dodge easily, or it could mean having impenetrable armor, or a few other things that represent one's ability to not lose HP. Increasing AC directly impacts survivability. The formula is calculated based on a combination of the type of armor worn, a modifier based on a lookup table for dexterity, and proficiency if the class has proficiency in the particular armor type.

Critical Condition

When a character is below 0 HP, the character is in critical condition. A character needs to "stabilize" to not die. Stabilizing occurs if a player can successfully win a 55:45 (10 or greater on a d20) bet 3 times before losing 3 times (IE: nearly a constant odds of 34% of living.) with a few other ways to automatically stabilize with healing magic or first aid skills, or forcing an automatic "tails" coin flip by receiving more damage before stabilizing. A character can die immediately if an attack deals more than their maximum HP in one move while in critical condition.

In Summary:

• HP is an abstract concept that represents many concepts of vitality, and not necessarily wounds. Therefore, recovering large amounts of HP is easy, even by mundane means. Maximum HP is determined by a formula that is calculated from a character's class and constitution attribute.
• Armor Class is an abstract metric that measures ability to not incur physical stress from a fight, and has a somewhat complicated formula involving the character's Dexterity, the armor they wear, and their proficiency bonus.
• A character in critical condition is on the cusp of death, but the mechanics for not dying are very simple. There is no simple advancement mechanic for improving a character's ability to recover from near fatality, though some tangential abilities can be used to those ends.

Fate

Fight Skill

The Fight skill is used for both making attacks and for defending against attacks. This makes for a very highly abstract skill that means that the person that is good at hitting things is just as good at not getting hit by other things.

Stress Tracks

A character in vanilla Fate has two "stress tracks" used for absorbing "physical" or "mental" damage. These are called "Physique" and "Will" respectively, and are based on skills of the same name. Increasing the Physique or Will skills to certain thresholds increases the ability to shrug off physical or mental stress. The stress tracks have boxes of various point values that can contain degrees of stress equal to that box. For example, a character with very high physique might have a 1,2,3, and 4 point stress box. If they incur a "2-shift" stress, it can fit in the 2,3, or 4 box, but each box can only hold one stress, so it usually makes sense to put it in the smallest box that fits. If there are no big enough boxes to hold the stress, it is converted to a more impactful "Consequence", that isn't easily shrugged off. Stress boxes "recover" very quickly, and only take a minute of rest between action intense scenes.

Consequence

Consequences have a similar point box scheme as stress, but they last much longer. Consequences use the nearly free form "Aspect" concept of Fate to describe what they mean, and under the most simple circumstances, the same track of consequences is used the same for both mental and physical consequences. Unlike the stress track where a consequence's shift needs to fit inside one box, it can be split between a consequence and an easily recovered stress box, so for example, a 6 shift could be placed in a 6 point consequence, or a 4 point consequence and a 2 point stress. The consequence is given a free-form name, and in regards to melee combat, probably describes a wound, with a small 2-shift consequence being something like "Bruised Hand" and a large 6-shift consequence being something like "Compound Fracture".

Recovering from a consequence requires overcoming a challenge equal to the point shift of the consequence, and replacing it with an intermediary aspect, like "Compound Fracture" might become "Leg in a cast". Once a consequence is in recovery, its aspect is not removed until a suitable amount of time has passed: "mild" consequences require a "scene", "moderate" consequences require a "session", and "severe" consequences require a "scenario".

The worst possible consequence, a special type, is an 8-shift "extreme" consequence that may happen only once per "milestone". These never recover and permanently transform a character. A melee extreme consequence might be "Lost Arm" or "Spinal Fracture". Even when these "recover", a permanent aspect will be inflicted, "One Armed" or "paraplegic" might be added to the character's aspects.

Conceding

The last line of defense is to concede defeat. Fate is a narrative game, so conceding defeat allows a player to choose to avoid specific consequences if it makes sense in context. If for example, a player does not want to die, they can concede so that the opponent can do anything to them except kill them. However, if the consequence that is to be avoided is not acceptable to the opponent (because, for example, his primary objective is to kill you, and there is no swaying him to any other outcome) then conceding is considered impossible and the battle continues. A character can only die then if the group decides that death is a dramatically appropriate consequence for the setting and situation: perhaps dying to a no-name thug is not dramatically appropriate, but then maybe a moving party saving sacrifice is appropriate, in which case the group agrees it is a fine way for a character to go out. If a character does not concede, then the consequences are up to the victor in the conflict and the player is "taken out".
So in summary:

• All damage from melee combat can be avoided by having a high Fight skill level.
• Stress tracks based on the Physique skill allow a player to absorb damage with no ill effect; they heal very quickly.
• Consequences give the character a long term consequence for physical trauma, and recovery times are commiserate with the severity. An Extreme Consequence never fully heals, and permanently etches itself on a character's concept.
• A character can concede a conflict if he does not think he can win in order to have a say in the consequences. If he (or she) does not, or cannot concede, when he (or she) is taken out, the victor decides the dramatically appropriate consequences.

Savage Worlds

Parry

Parry is a static number in Savage Worlds, that operates a little similar to active defense in GURPS or Armor Class in D&D. It is directly related to fighting skill: it is Fighting/2 +2. So if a user has a Fighting skill of 8, then he has a parry of (8/2)+2 = 4+2 = 6. A parry is able to entirely prevent damage.

Toughness

Toughness is similar to GURPS' DR. It is calculated based off of the main attribute, "Vigor", with bonuses added for armor. Similar to parry, it is Vigor/2 + 2 + Armor Bonus. Toughness directly subtracts damage received if a parry failed. For example, if a player rolls 10 damage against a character with toughness of 7, he will do 10-7 = 3 damage.

Shaken

A character is "shaken" if the damage rolled against them is greater than their toughness. A player loses turns until they can beat the shaken state by rolling better than 4 with their Spirit attribute. If a character takes enough damage to get a "raise" (The number of +4's above a character's toughness) they also acquire one "wound" per raise. If a shaken character receives damage, the damage already counts as a "wound".

Wound

Each wound a player takes gives them a -1 penalty. A wound can be "soaked" by spending a "bennie" (A special token; all players receive a certain amount at the beginning of a session) and rolling against Vigor; they can remove one wound for succeeding, and one wound for each raise. A player character can take 3 wounds before being in danger. At this point, a player must roll against Vigor. Success with a raise allows them to remain conscious. Normal success allows the player to fall unconscious, but not die. Failure means that the character is dying and needs medical care. Every turn in battle, a dying person must roll against Vigor to stay alive. A roll of 1 means death.

Summary:

• A high parry means a character doesn't get hurt at all. Parry rises when Fighting skill is increased. The formula for parry is simple.
• Toughness allows a player to shrug off damage that made it through a failed parry. Toughness can be improved by raising vigor or buying better armor
• A character is shaken if they receive damage greater than their toughness. A character is easy to wound when they are shaken, and can potentially lose many turns.
• A character that is damaged by a large amount or damaged when shaken accrues wounds. Three wounds put the character in a critical state where dying is possible. Characters with high vigor can survive easier. Using specially limited "bennies" a character can remove his own wounds by "soaking".

Ryuutama

Hit Points

Hit Points are an abstraction of both stamina and ability to absorb damage. At 0 Hit Points or worse a character is unconscious. A character dies if she reaches a value equal to -1*condition, which has a chance of changing every day. A character's starting hit points are determined by their starting strength (STR), and is simply STR*2.

With each additional level a character earns, they have an opportunity to distribute 3 points between HP and "Mental Points" (MP) Hit points can recover quickly through mundane means like resting, and even faster through magical means.

Condition

"Condition" is determined each day and is a general sense of how the character is feeling. Condition is determined by rolling STR + Spirit (SPI), both stats can be raised when character level increases. Condition among other things determines the threshold where a character may die instead of going unconscious.

Initiative

"Initiative" is similar to initiative in D&D in that it determines turn order, but it also has one important additional effect in that it acts to determine a character's ability to avoid damage, like parry in Savage Worlds. Initiative is rolled at the beginning of every battle, and is equal to Intelligence (INT) + SPI. If a player wants, they can change their initiative by using a turn to "Evaluate" thus potentially increasing defense and moving to a better position in the turn order queue. If a character equips a shield they can alternately elect to use the shield's "Dodge Value" instead of their initiative value to avoid damage; this does not change turn order, but allows a player to have a bare minimum protective value at all times.

Defense Points

Defense Points work like GURPS' DR mechanic and are based on the armor and shields equipped by a character. If a character has 2 Defense Points and is dealt 3 damage, then they receive 3-2 = 1 damage.

Summary:

• Hit Points measure vitality, and the equations to increase them are simple.
• Condition determines threshold at which a player dies. The formula is always on the character sheet, so it is easy to remember.
• Initiative determines a character's ability to avoid damage and is based on INT and SPI. Using a shield guarantees a minimum value even if a player rolls a poor initiative.
• Defense points simply subtract damage received, and they can be increased by buying more valuable weapons and shields.

Summary and Other Observations

The system with the least numerous mechanics to consider is surprisingly D&D 5e with 3, while the rest have 4; this probably has to do with the fact that there is no "Damage Resistant" metric and it is abstracted into what other systems might call active defense, parry, or dodge. Fate required the most explanation of all sections (even more so than GURPS, surprisingly) simply because the system is so different, and the concepts need to be explained in more detail. An interesting observation is that GURPS, Savage Worlds, and Ryuutama actually all have roughly the same amount of defensive mechanics to be aware of; GURPS does have a more mechanically intense "Active Defense" system than Savage World's "parry" or Ryuutama's "Initiative" or "Dodge Value", but they all follow roughly the same pattern of:

1. First line of defense to not receive any damage (Active Defense, Parry, Dodge)
2. Second line of defense to absorb damage (DR, Toughness, Defense Points)
3. Final line of defense to absorb damage (HP, Wounds, HP)
4. Test to stay alive if all else fails (Roll against HT, Test Vigor Trait, Compare Condition)

D&D, Ryuutama, and Savage Worlds all took around the same amount of text to explain, and Fate and GURPS took a little bit longer to explain than the other three. All of these calculations are performed before battle and for the most part, can be performed on downtime, except for the effect of encumbrance on dodging in GURPS, which can become complicated if playing with complete inventory management rules.