RPG:Combat mechanics

Combat is expected to be at the forefront of any RPG game, so it naturally warrants its own mechanics.

Turns
During combat, a single turn is roughly equivalent to six seconds in the game world. Each turn is subdivided into two phases: the planning phase, and the execution phase.

During the planning phase, each of the two opposing sides plan out their actions. During the execution phase, both side's planned actions are simultaneously executed, with differing success. Generally, during the execution phase, all action by player characters and non-player characters alike is involuntary. When two characters decide to attack each other at the same body part during the planning phase, it is very likely during the execution phase that one of them will parry the attack, effectively wasting that turn.Should a combatant commit a particularly punishable move, such as a clumsy attack (failed roll against dexterity), the target has to take a roll for willpower. Should the roll fail, the character will commit an involuntary action: instinctively counterattack. Should the roll be succesfull, the character1s controller can decide whether they wish to counterattack or not, and if yes, then how exactly, effectively granting them an extra turn.

A turn can also be spent by simply moving rather than attacking or casting a spell.However, this tabletop roleplaying system does not define any system for mapping movement, attributes and turns together, so players have to make up house rules for defining movement on a grid-based system. Under house rules, a turn can also be spent doing other potentially important actions, but hostile combatants may in turn intercept said actions and attack the character.Since combat happens on two phases and players may not be able to necessarily anticipate hostile actions during the planning phase, they may give conditional orders to their own characters, such as "retaliate if attacked (in melee)" or "attempt to parry or block attacks but do not retaliate if attacked".

To sum up:


 * 1) Planning phase: Each side decides what actions their characters intend to commit during this turn. Characters with high dexterity may plan more actions, as they may be fast enough to actually complete them.
 * 2) Execution phase: Each character attempts to commit their actions. Since targets and action-commiters will inevitably overlap, the intended actions of certain characters will be intercepted, causing a roll againt willpower to decide if the interrupted character's next action will be involuntary or player-controlled.
 * 3) The results of the turn are evaluated before the next turn may begin. Any damage done to characters is documented. Characters with negative status effects that prevent action are forced to skip the next turn. Damage done by negative status effects like poison and bleeding is evaluated.
 * 4) The turn is over, and the planning phase of the next turn may begin.

During each attack - melee or ranged - the character's dexterity is measured up with a randomly generated or dice-rolled number.


 * Targeted Strike: The character targets a specific body part of the enemy. On every strike, they roll either two 10-sided dice or four 5-sided dice (or use a random number generator to generate a number between 0 and 20), where randomness is measured up to the character's Dexterity stat. If the number is below the character's dexterity minus four, the strike is a success and hits the intended body part (if it was a targeted strike) - if it's between dexterity minus four and dexterity, it's a "bittersweet success" and the character hits a neighbouring body part instead (in case of torso: the neighbour is randomly picked, RNG or single 6-sided dice roll). If the rolled number is above the character's dexterity, it's a miss.
 * Untargeted Strike: The character simply swings their weapon in the enemy's general direction. A random number is generated or rolled between 0 and 20. If the character rolls below their dexterity plus two, it is a success, if over their dexterity plus two, a failure. The body part that gets damaged is decided randomly - which is discussed at the Body parts section of this document later on.

By default, involuntary counterattacks are always untargeted.

Melee Attack
Melee Attacks are attacks done with a melee weapon up close. If both combatants are fighting with bladed weapons (swords), both combatants roll for a succesful hit and are trying to attack the same body part, and neither parties indicated any desire to prioritize defense over offense, they parry each other's attacks, leading to no damage - if one character decides to prioritize defense over offense, then any succesful roll for hitting will translate into parrying, no matter the targetted body part. It is impossible to parry with or against any melee weapon other than bladed weapons.

Attack Types
Melee Attacks can be neatly divided into four categories:


 * Regular Attack: A regular targeted or untargeted strike with your melee weapon. It has no drawbacks or advantages. All involuntary counterattacks are also regular attacks. All characters know how to do regular attacks by default too.
 * Power Attack: An untargeted strike done with a greater swing, from a large distance, with a stronger momentum - this results in a stronger, but more inaccurate attacks, this means a 30% increase to chance of miss, but also a 25% to all damage done in melee. By default, characters cannot do Power Attacks, and must unlock them via a feat - in the archmodule, that feat is Overswing.
 * Quick Attack: Two untargeted strikes per at a turn, but each with an extra 30% increase to chance of miss, and also a 30% to all damage done in melee in case of landing a hit. By default, characters cannot do Quick Attacks, and must unlock them via a feat - in the archmodule, that feat is Flurry.
 * Mounted Attack: A specialized untargeted strike from atop a mount (usually a horse), it requires the attacker to be moving while doing the attack (otherwise it's just a Regular Attack done from horseback) - by default, this kind of attack comes with a 40% at the cost of an extra 15% chance to miss the target. Just like Power Attack and Quick Attack, this needs to be unlocked via a feat - in the archmodule, that feat is Chevauch"e.

Unarmed Attacks
When doing unarmed attacks, the damage done equals the character's Strength attribute, unless some feats modify that. It is always Crushing type damage.

Ranged Attack
Ranged Attacks are attacks done from afar with projectile-based weaponry. whether it be a simple rock or an arrow. Because attacking enemies afar requires much greater precision than attacking enemies up close, there is usually a much greater Dexterity-malus for untrained use of ranged weapons. Realistically, distance should also be a factor, but as this system won"t even create a grid or map system, it will be up to the DM's discresion to decide how much will distance affect accuracy.Without any skills or feats to negate it, using ranged weapons while on a moving mount grants a to Dexterity.

Damage
During combat, it is inevitable, that characters will sustain damage, sometimes even lethal damage. However, it is important to distinguish between different types of damage characters may sustain, as they may different kinds of resistant to different types of damage. Keep in mind, that most weapons and offensive spells typically simultaneously inflict two or more types of damage!


 * Physical: The most common type of damage, this encapsulates all forms of "mundane" types of damage that can befall upon mere mortals, anything that doesn"t involve magic.
 * Crushing: Damage done to entities via applying blunt force to a relatively large area on the target. Since every weapon in existence has weight behind it, every weapon - at least, every melee weapon - inflicts some level of crushing damage upon the intended target, even if we"re talking about sharp blades. Fists, quarterstaffs, cudgels, hammers and maces inflict only crushing damage. Among ranged weapons, slings cause crushing damage. Depending on the type of ammunition (chiefly the shape of the bullet), firearms can cause both crushing and piercing damage.
 * Slashing: Damage done to entities via severing tissues, creating cuts. This type of damage is perhaps the most deadly to unarmoured and naked people, but is not much of a worry when the target is wearing armour, as most types of armour grant near-complete immunity to slashing damage. Among other things, bladed weapons (swords, daggers, scimitars, sabres, etc.) and axes deal slashing damage when swung against the target.
 * Piercing: Damage done to applying pressure onto a rather small area, a small point on the target. This type of attack is very affective against not just unarmoured opponents, but also opponents wearing chainmail or any kind of armour not made out of solid metal. Plate mail, breastplates and other more solid metal armour however offers near-complete immunity to piercing attacks. Among melee weapons, piercing damage is primarily caused by spears and pikes, but can also be caused by bladed weapons of any kind, when they are used in certain ways (stabbing with knives and daggers, half-swording with swords, etc.). Among ranged weapons, javelins, bows and crossbows cause piercing damage. Depending on the type of ammunition (chiefly the shape of the bullet), firearms can cause both crushing and piercing damage.
 * Thermal: Damage done to entities via applying heat that's beyond what their body is capable of tolerating, whether too cold or too hot. Cold thermal attacks cause frostbite, while hot thermal attacks cause burns. Thermal damage can be dealt not just by hostile entities, but by the environment itself, or even a character's own equipment (chiefly their clothing or armour).
 * Cold
 * Hot
 * Biological: Damage done to entities via various biological processes, such as poison or disease.
 * Magical:
 * Energy: Damage done to entities via exposing them to destructive spells made out of pure magical energy. Even though this description sounds rather intimidating, such spells tend to be the weakest of the destruction spells. The only way to resist them is to have Magic Resistance.
 * Elemental: Subdivided into four more groups (Earth, Air, Water, Fire), elemental magical damage represents damage done via Elemental Magic. Resistance depends on both general Magic Resistance, as well as Resistance to that specific element.
 * Earth: Usually co-occours with Crushing damage.
 * Air: Usually co-occours with Crushing, Slashing or Piercing damage.
 * Water: Usually co-occours with Cold Thermal damage and Crushing damage.
 * Fire: Usually co-occours with Hot Thermal damage, sometimes with Crushing damage.