In the Dungeons & Dragons role-playing game, game mechanics and dice rolls determine much of what happens. These mechanics include:
All player characters have six basic statistics:[1][2][3][4]
An ability score is a natural number, with a value of 10 or 11 representing average ability.[5] "These ability scores help determine whether [a] character succeeds or fails at something they try" when a player rolls a d20.[6] For example, "a Dwarf with 15 strength can probably lift up a huge rock quite easily. A wizard with 6 wisdom probably won't realize when they're getting conned. A bookish monk with 20 intelligence but just 4 constitution [...], would intuitively know the perfect regimen for training for a marathon, but couldn't even come close [to] completing one".[6]
Beginning with the 3rd Edition, each score has a corresponding ability modifier, where Modifier = Score − 10/2, rounded down.[6] It acts as a bonus or penalty depending on a character's ability scores. This modifier is added to the appropriate dice rolls.[6][7] For example, the strength modifier would be added to the damage dealt by a sword, the dexterity modifier to Armor Class (see below) as the character's ability to dodge attacks, and the charisma modifier to an attempt to smooth-talk a merchant.
In AD&D, ability scores were "determined by rolling three 6-sided dice and adding up their values".[8] This had a significant impact on character creations as "certain classes could only be taken up by characters with the right combination of statistics. As a result, players often" re-rolled characters until they ended up with the combination of ability scores they desired.[3]: 149 The point buy system was originally added as an optional ruleset in the second edition supplement Player's Option: Skills & Powers (1995) and while it is "largely incompatible with most of the other books released for AD&D second edition" it still "proved very popular among fans".[9] "A point system to ensure total player control over the character's attributes while at the same time limiting just how powerful the character could become [...] [was] formalized in the third edition".[3]: 149
There are now several methods of determining a character's initial ability scores during character creation:
Armor class (AC) is a rating used to determine how difficult it is to damage a creature/character. It is based on several factors such as a creature's natural aversion to physical injury, magical enhancements, and any protective garments worn.[3][5] The dexterity ability score grants bonuses to AC.
In 4th edition, there are three defenses that function similarly to armor class. Fortitude is based on strength or constitution; it represents a character's endurance to pain. Reflex is based on dexterity or intelligence and can be modified by a shield; it represents a character's ability to dodge. Will is based on wisdom or charisma; it represents a character's strength of mind and resistance to mental attack. These defenses are typically lower than AC, so an attack against fortitude is usually better than an attack against AC.[7]
Hit points (HP) are a measure of a character's vitality or health; they are determined by the character's class or race, and Constitution score. Hit points are reduced whenever a character takes damage.[2][3]
In the original D&D game a character died when his/her hit point total reached 0. First edition AD&D introduced an optional rule in which a character died when his/her hit points reached -10, with beings falling unconscious at 0 HP, and creatures reduced to negative HPs continue to lose HPs due to bleeding, etc. unless they are stabilized by aid or healing (natural or magical). In third edition, this rule became part of the core rules.
In 4th Edition, death occurs when a character's hit point value is reduced to half their total expressed as a negative number.[7] For example, if a character has hit points of 52, the character is unconscious and dying at 0 hit points and death occurs when the character's hit points reach -26.
In 5th Edition, a character is killed automatically if the damage is greater than the negative value of their maximum hit points. Otherwise, a player at 0 hit points must begin making "death saving throws", where an unmodified d20 roll resulting in 10 or above is a success, below 10 a failure. If the player gets three failures before three successes, the character is dead. If three successes are recorded, the character is stable but unconscious. A result of 1 counts as two failures, while a result of 20 is automatic success and the character regains 1 hit point. A fellow player may attempt to stabilize their companion using a medicine skill check, or use more advanced healing options.[12]
Certain situations give characters the chance to avoid special types of danger or attacks. These chances are called saving throws or saves. A saving throw is made when a character would come to harm from extraordinary means such as poisons and magical compulsions in nature.[5]
In the early editions of D&D, there are five categories of saving throws, based on the form of the potential damage:
In 3rd Edition, they were reduced to three kinds of saving throw based on what aspect of the character was under threat.
In 4th Edition there is only one type of saving throw.[7] Saving throws are usually rolled after a character has already been affected by an attack (by hitting the character's AC or fortitude, reflex, or will defense, defenses which the 3rd Edition saves had been converted into), rolled each round to give the character a chance to shake off the effect. They are meant partly to simplify record-keeping for effects that last more than one round but less than the encounter.
In 5th Edition, saving throws are explicitly tied to the ability scores, and carry their names, resulting in six categories of saves. A saving throw is performed similarly to a skill check, with a d20 roll result added to the relevant ability modifier and, if applicable, the proficiency bonus.[12]
When a character makes an attack, a 20-sided die is rolled to determine success/failure. The result could be adjusted based on any number of possible modifiers the character or its intended target have.[5]
The number added to the die roll is actually several different modifiers combined, coming from different places. These modifiers include the character's proficiency with the specific weapon and weapons in general, the quality of the weapon (masterwork craftsmanship or magical enhancements), the modifier of the ability associated with the weapon (strength for melee weapons, and dexterity for ranged weapons), magical effects improving/hampering the character's ability to attack, and any special experience the character has fighting a certain foe.[5]
The combat mechanic is turn-based and operates in rounds.[5] A round is a discrete time interval (approximately 6 seconds, game-time in later editions, and approximately 1 minute in earlier editions) in which all involved parties act in the combat. The order in which parties involved in the combat act is determined by Initiative.
As the game is played, each PC changes over time and generally increases in capability. Characters gain (or sometimes lose) experience, skills[23] and wealth, and may even alter their alignment[24] or gain additional character classes.[25] The key way characters progress is by earning experience points (XP), which happens when they defeat an enemy or accomplish a difficult task.[26] Acquiring enough XP allows a PC to advance a level, which grants the character improved class features, abilities and skills.[27] XP can be lost in some circumstances, such as encounters with creatures that drain life energy, or by use of certain magical powers that come with an XP cost.[28]
Dungeons & Dragons, starting with AD&D 1st Edition and continuing to the current 5th Edition, has many skills that characters may train in.[29][30][5]
A skill check is always a d20 roll, with bonuses added. Sometimes, a skill check may be aided by favorable circumstances (such as you brandishing a weapon while using Intimidate) or hampered by unfavorable circumstances (such as using improvised tools to pick a lock).[5] A skill check is successful when the roll is higher than or equal to the difficulty class (DC) of the task. Usually, the Dungeon Master sets the DC. Sometimes the DC is set by the result of something else's check, this is an "opposed check". An example of an opposed check is spot against stealth: the character is trying to see something else that is trying not to be seen.[5]
Feats were introduced in 3rd edition of Dungeons & Dragons. A feat is an advantage, often some special option for the character (such as a special combat maneuver) or some modification to game options and the mechanics involved.[3][5] Feats can be contrasted with skills, which were also introduced in the same edition, in that using a feat does not usually require the particular success/fail roll that skills do. Instead of possessing a certain rank at a skill, a character either possesses a feat or does not. Many feats require certain prerequisites (such as related feats or minimum ability scores) in order to select that feat.[33]
The 4th Edition feat system is similar to the system in 3rd, with each feat having any number of prerequisites and some beneficial effect.[7] Feats are also categorized by type, though "general" feats lack a category. "Class" and "Racial" feats require the character to be the indicated class or race. The "Heroic", "Paragon", and "Epic" descriptors indicate that the character must be in that tier or higher in order to choose the feat. "Divinity" feats grant a character with the "Channel Divinity" power an additional, alternative use for that power.
In 5th Edition, feats are made an optional character customization feature. As characters advance, at certain levels players increase their characters' ability scores. If playing with feats, they may forgo the ability score increases to take feats, which are structured as a package of thematically related improvements, some of which have prerequisites.[12]
{{cite book}}
Attack Roll: If your result equals or beats the target's Armor Class, you hit....