Fighting happens like this: every character in the game has limbs they can use to strike (they can have weapons, or be used bare).
== Weapon damage
When a character strikes, the weapon damage is computed based on the weapon used and the character's skill with it (the weapon may perform some checks or randomization of values of its own, and so do the enchantments on the weapon). This damage is under the form:
For instance, for an ice-enchanted iron katana:
(500,ice) (100,ice&iron) (300,iron)
== Base damage
Damage is then reduced or amplified based on the defender's resistance. This resistance is an association of the form:
For instance, a demon (immune to iron, vulnerable to ice) would have:
So the base damage inflicted by the weapon here is:
(500 * 2)+ (100 * 2 * 0.5) + (300 * 0.5) = 1250
== Inflicted damage
Once the base damage is computed, the actual fight algorithm enters into action.
The first check is the to-hit check: Attacker EQU/2 + RAP versus defender RAP / 2.
Increased concentration and speed help hitting the enemy, increased speed helps evading enemy hits.
The second check is the concentration check, to see if the attacker is being tactical or just bashing without thinking. This check is Attacker EQU versus Attacker BRU.
Increased concentration and low brutality help making good tactical decisions.
If the concentration check succeeds, the attacker attempts a tactical strike by checking Attacker EQU versus the enemy's 2*RAP.
Concentration helps performing successful tactical attacks, speed helps evading enemy tactical strikes.
If both checks succeeded, then the attacker inflicts:
10 * base-damage * random(1.0,2.0)
If one of them fails, then the attacker will simply perform a violent attack. These are usually less efficient than tactical attacks, however their strength depends on the attacker's BRU and the defender's STA statistics.
The attacker inflicts a base damage of 1, and then attempts a series of checks of his BRU against the defender's (STA/2 + Armor + Difficulty), where Difficulty starts at 0 and increases by 10 after each successful check. For each success, the attacker inflicts an additional base-damage * random(0.0,1.0), and this goes on until the attacker fails one check.
For violent attacks, brutality increases the damage you inflict greatly, while stability and armor decrease the damage received.
Luck also comes into account at each check. If you fail the normal check, but succeed at the luck one, then it is as if you had succeeded the normal check. If you succeed both luck and normal check, you make a miracle success and get damage bonuses down the line. On the defender's side, any succeeded luck check means immediate failure on the attackers side (no matter what checks he did).