Mortal Combat (NH)

Mortal Combat
For all combat, players may choose to ignore these rules if they agree on a result OOC. 
A group's combat strength is defined as follows: 
4 + number of boons - number of challenges + Exarch bonus + Avatar Bonus + Defensive Action - Attrition 
Combat Exarchs provide a +2 bonus to combat if they are noted to be present at a battle 
Avatars provide a +4 bonus to combat if they are present. 
Wars take place as discrete battles.  For each battle, the attacker (the player who spent a guide action to lead a group into war) determines a target or 'goal' for the battle.  This can involve taking control of a boon granted to the other side (if it makes sense to be able to do so), to force a particular action on the part of that civilization, or even capturing a particular city or town.  The defender (can be anyone, but ideally someone who has a vested interest in the group) sets the 'setting' of the fight, what location the battle will take place at (if at all).
Once these decisions have been made, the strengths of the armies present are added to one another and the proportional strength of each side is determined, rounded to the nearest whole percent. 
Example:  if the attacker has a strength of 20 and the other has a strength of 10, then the total strength at the battle is 30 and the proportional strength of the attacker is 66%.
At this point, a D100 is rolled for both the attacker and defender.  Each die is compared to their respective proportional strength.  If the roll is equal to or less than their strength, they are considered to have 'won' the battle.  This results in four possible scenarios.
Attacker Succeeds, Defender Loses:  The attacker has won the battle, and achieves their short-term goal (effects of which will be applied at the end of the war).
Attacker Loses, Defender Succeeds: The attacker is repelled and bloodied by the defender.
Attacker Succeeds, Defender Succeeds: The battle ends in a bloody and harsh stalemate
Attacker Loses, Defender Loses: The battle ends in a stalemate with neither side being overly damaged.
If the Attacker Succeeds, and the Defender Loses, the Attackers are considered the winner, and their goal occurs.
A Goal can be one of the following:
-The Defender loses control over a particular location, city, or outpost. (The elves conquer the dwarven city of Mon Harro)
-The Attacker may make a free Guide action at the battle site (The Dwarves desecrate the branches of Yggdrasil after driving the Elves away)
-The Attacker wrests control of a particular boon, depriving the Defender that boon for the rest of the war. (The Elves wage a series of Guerrila strikes on Dwarven Traderoutes, interrupting the supply of warmetals to the front). This boon can no longer provide a bonus to any side in the current war. If the boon is tied to a particular location, it may remain under control of the attacker when the war ends.
Attrition:
Attrition is calculated based on whether the opposing side won or lost their roll.If the opposing side won the roll, then the civilization's combat strength is reduced by X%, where X is the proportional strength of the opposing side at the battle. 
If the opposing side lost the roll, then the civilization's combat strength is reduced by X/2%, where X is the proportional strength of the opposing side at the battle.
Combat strengths are always rounded down to the nearest whole number.
Example:  Two nations with combat strength 50 fight one another.
A: 50   B: 50
The first combat, A wins, B loses
A takes 50%/2= 25% losses, is reduced to 37.5 (rounds down to 37)
B takes 50% losses, is reduced to 25
A: 37  B: 25
The second combat, A wins, B wins
A takes 40% losses, is reduced to 22.
B takes 60% losses, is reduced to 10
A: 22  B: 10
A and B both lose.
A is reduced by 16% to 18
B is reduced by 34% to 6
A: 18 B: 6
A loses, B wins!
A loses 25% to 13
B loses 37% to 3
Etc.
Control of the war now shifts, with the attacker becoming the defender and the defender becoming the attacker.
After a war is finished, attrition decreases at a rate of 50% the nation's non-attritioned strength per week. e.g., a nation with 30 strength and 50% attrition would move from 15 to 22 (7 is half of 15, rounded down) the first week, and recover fully to 30 (11 is half of 22, but capped at 30) after the second.
Additional rules: 
After the initial attack action, any attacker may declare that their goal is 'to defend.'  This results in a +2 bonus to their combat strength at the cost of not achieving anything in the case of a victory.  If both sides declare defensive actions on 2 consecutive rounds of combat, the war is considered over, and must be reinitiated with an additional guide action.  The war is also considered over by OOC agreement or if one group reaches a strength of 0.
A warring nation may choose to send only a portion of their strength into battle (minimum 1 strength or 25% of total, whichever is higher).
Category: Rules (NH)