The description below only applies in the main warzone, and not in the new starter mini-RvR warzone introduced and updated further during May 2021, called Squid Island.
Background
In multiplayer pvp games, we believe it is very important that the mathematical formulas on how armour and damage and combat works are fully disclosed to the public. This allows the developers and players to be held accountable for how the combat system operates and how it is used.
This article is an attempt to explain how the Armour and Damage system of the game works. The explanation is the result of the hard work of players in reverse-engineering the system. It is believed the developers did once have access to the formulas, but they have now been lost or have become too undecipherable in the source code, with the passage of time.
This article is primarily the result of an attempt to understand and summarise the detailed efforts of players in key official forum posts such as this: https://www.championsofregnum.com/forum/showthread.php?t=94209 . Such forum posts have been stickied in the official forums so all new players can review the detailed results of these efforts. This article is not a perfect exposition, does not draw the finer distinctions between competing theories, does not claim to be precise, but is merely an attempt at a synopsis.
Step One: Calculate total Armour Points ("AP")
Each item of armour, contains grades ranging from Very Bad, Bad, Normal, Good, Very Good and the rarely seen Excellent. The adjustments applied by these grades range from -60% to +90%.
Each type of armour contributes a certain percentage to the total AP.
Archers and Warrior classes gain an automatic 33% bonus to AP.
Each class applies a further Class Adjustment to their total AP.
Bonuses described as "Protection %" addition or deduction are bonuses applied to the total AP.
A further class bonus is applied to AP as follows: Archers 50%, Warriors 55% and Mages 60%.
Step Two: Calculate the Damage
This is a simple matter of just calculating the damage as stated on the weapon. You then add the primary attribute for each class to the damage. Each class also has an adjustment to the primary attribute giving the bonus applied to produce the Damage figure.
The game does use a random number generator ("RNG") to calculate damage. When damage is specified to be say 50-60, then the game uses a dice roll of 1d10 to determine the damage caused.
The game does use a RNG to calculate whether the attack hits. All attacks are determined successful in hitting, unless defeated by Evasion and Resist rolls. Whether the attack is successfully evaded or resisted is subject to a RNG roll.
Step Three: Adjust the Damage for the AP
In basic terms, the damage inflicted upon the player = Damage minus AP.
However this formula is adjusted in the following way.
Count the number of Damage Types caused by the attacking player. The game has six Damage Types: Slash, Pierce, Blunt, Fire, Ice and Lightning.
Divide the AP by the number of Damage Types, giving "Adjusted AP".
Each Adjusted AP is then modified by the % bonus applied by the defending player's items for each Damage Type resistance. This gives AP Adjusted for Type Resistance ("APAT").
Calculate the amount of damage caused by the weapon in each Damage Type, giving Adjusted Damage for each Damage Type ("ADAT"). This is a simple matter of calculating the damage type based on all the items of the attacking player.
The Final Damage inflicted on the defending player is then the sum of ADAT minus APAT for each Damage Type.
Conclusion
The effect of the general formula above is to encourage:
a) Attacking players to have as many Damage Types in their weapons as possible. This forces the defending player's armour to be divided amongst different Damage Types.
b) Attacking players to focus on perhaps maximising one or two preferred Damage Types in their weapons as possible. This helps maximise the amount of ADAT for a given Damage Type, and maximise the Final Damage.
c) Attacking players to maximise their class' primary attribute. This helps maximise Damage.
d) Defending players to maximise their armour items' total AP, Protection % bonus, % bonus applied to each Damage Type and to try to ensure the result of all the types of resistance on their armour items to each Damage Type, does not have any particularly bad rating for any Damage Type.
It is possible for attacking players to seek to decipher a particular defending player's lowest rated Damage Type, and to switch their weapons accordingly.