Udo's D20 Mass Combat

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1 WTF? This document was created with a single goal: to bring a unified mass combat model to the OGL D20 system that was as simple as possile while also retaining all the D20 combat features. There will be (almost) no tables of values to look up, and we really tried to bring down the number of special new rules and concepts to the minimum necessary. There are two main difficulties in converting the individual combat rules to a system of massive battles: groups of fighters will still have to interact with single creatures even in mass combat situations, and: the system has to be easily scalable to all kinds of battles from a few dozen to a few thousand creatures. With these objectives in mind we arrived at a very small set of new abstractions that make up the ruleset of system: Fighting creatures are organized into groups that fight together, some stats of the individuals will be averaged over the entire group (like AC) and some will simply be added up (like hit point. A group's current health is represented by a simple scale from 0 to 10 points. How many actual hit points are represented by one such point is dependent on the cumulative hit points of this group. A group's potential to deal damage is reprsented by a scale of group damage points ranging from 0 to 10. How many actual hit points are prepresented by one such point is dependent on the cumulative damage the group can deal in the current attack mode. That's it, basically, as will be described on the following pages. But why was a 0 to 10 point system chosen? The answer is simple, but multiple: It reduces latency in gameplay Keeping track of a few low-order stats is way faster than doing it with many values that are sky-high. combat system (in order to accurately represent the scale of things) to the part of the game where the combat units are created, rather than later when they are played, complexity is reduced. Transparency A 0-10 scale provides a fast way of deciding the relative health of a group. Game mechanics Groups Due to the laws of probability, in mass combat, decisions are not just boolean - meaning attacks and defenses don't just succeed or fail completely. Dealing with 0-10 scales brings us a nice way of handling the relative quality of damage and other effects. A group is a unit of creatures that band together for battle. Each group has a group leader who issues orders and directs the actions of the group. Initiative Initiative is an averaged score. To determine the group's overall initiative modifier, add the initiative modifier of each member and then divide by the number of members present. Any fractions are rounded down. AC & Saving Throws Armor class and saving throws are averaged scores, meaning the group's AC and saving throws are the averaged scores of all its individual members. To determine the armor class of the combat unit, calculate the average of all its members. This is especially easy when the combat unit is homogenous, where all members have the same stats. The saving throw bonuses average of all members is used to determine the combat units overall saving throw bonus. It reduces complexity By offloading the necessary multiplication and division operations that have to occur in a mass

2 Hit Points & Force Strength The group's FS (or force strength) is a cumulative score. Add together all the individual members' hit points and divide them by 10. The FS represents the group's resistance to damage. FSP or (force strength points) is a value ranging from 0 to 10, indicating a combat group's combat readyness. Every group starts out with an FSP 10. This number gets reduced later during battle if the groups takes damage and is reduced as a result. Group Damage Group damage is a cumulative score indicating the group's ability to deal damage. The amount of damage a combat unit deals depends on its weapons. Take the average amount of damage a weapon deals and multiply it by the number of members in the combat unit. The result is the average amount of total damage the combat unit can deal in a single round. Divide this by 10 to get the group damage score. For example, a goblin with a dagger can deal an average of 3 points damage (1d4), therefore a combat unit of 50 goblins deals 150 points of damage on average, placing the group damage score at 15. Alternate Attack Modes Sometimes, a group can employ more than one means of attacking an opponent. For example, it may be capable of both ranged and close combat. Calculate the group damage for each of these attack modes separately. Most times, a group has more than one attack mode, considering different weapons and/or spells that member of the group can use. As a rule, the group can use one attack mode per round in order to keep things simple. Mixed Attack Modes While alternate attack modes describe what happens if everybody in the group is doing the same thing, mixed attack modes describe one part of the group doing one action while another is simultaneously doing something else. As a rule, a group can only have mixed attack modes with two different forms of attack each: for example a ranged and a melee attack form combined into one mixed attack mode. Mixed attack modes are only possible if there are at least 10 group members available. Dealing Damage By default, a combat group deals 10 GDP of damage to its apponents. However, this amount if modified by the following factors: Force strength points: If the attacking group has sustained losses to its FSP, the amount of GDP it deals with every attack is reduced by the same amount. Attack roll: The attacking group has to make an attack roll to overcome the defenders' armor class. If that attack roll fails, calculate by how many points the attacker missed. Then, reduce the GDP by that number. Environmental or situational modifiers: The GM may, upon their discretion, modify the GDP dealt by an attack as a result of special circumstances during the battle. After these three factors have been considered for each attack, the resulting number of GDP is the damage caused whereas each point of GDP represents a number of hit point damage according to the GD (group damage score) of the attackers. Obviously, a GDP below 1 means no damage is caused by the attack. Example: a group of 50 goblins has a GD score of 15. They attack a group of villagers which has an AC of 11 with an attack roll result of 7. Thus, 6 GDP are caused by the attack (10 minus 4), which equal 60 damage points. Receiving Damage To calculate how a defender group's FSP is reduced by the attack, divide the amount of incoming damage by the group's FS score (fractions are rounded down). Example: the group of Goblins in the example above causes 60 points of damage to the group of villagers. Say the villagers have an FS score of 35, this means their FSP is reduced by one as a result of the attack (60:35 = 1, fractions rounded down).

3 Leadership To command a group in battle, leadership rolls are required from time to time. In this event, the group leader performs a leadership roll. To lead, either the sense motive or the intimidate skill can be used. Also, if the leader has the leadership feat, she gets a bonus +6 synergy bonus to any leadership rolls. Morale A group's morale is essentially the difficulty that the leadership rolls have to be made against. The morale base value of a group is 15. The following things influence this score further: +4 if ¼ or more of members chaotically aligned -4 if ¾ or more of members lawfully aligned +4 if group's FSP is reduced below half +1 for every 10 members *** other modifiers (GM's discretion) Special Considerations Damage Recudction Group damage reduction is a cumulative score, meaning the DR of each individual member gets added up and divided by 10. The result is a bonus to the group's FS score against attacks where the DR type applies. Movement A group can move as fast its slowest member. The normal D20 movement rules apply, however, the situation can arise where a group's movement is not enough to move one square ahead at a time. In this case, the group can still move one square ahead regardless, but it may not engage in any other action this round. Multiple Attacks Many beings are capable of making more than one attack per round. Just average the total attack bonuses of all the creature's attacks when it comes to calculate its attack bonus. Likewise, simply add up the average damage caused by each attack. Regrouping Once a battle progresses, combat groups can be worn down pretty fast. Sometimes it is advantegous to regroup two ore more partially depleted groups into one or more full ones. To make this move, a successfull leadership roll is required for all participating groups. Space Requirements If you plan on using a combat grid to visually display the groups' positions (and you really should), it's important to know how much space the unit occupies. This is a logical extension of the normal D20 rules, where a normal-sized creature occupies a 5 foot square. In mass combat, every creature in the group still has the same space requirements, which means you can just add up all the members' squares to arrive at the total space needed for that group. Now, this number of squares is just scaled according to the layout of the mass combat battlefield. For battles with a small number of participants, a square now represents 25 normal-sized (five foot) squares total, meaning a single 25 by 25 foot square. Obviously, this is the space required by 25 mediumsized creatures. For larger scale battles, let each square on the field represent 100 normal-sized squares total, meaning a single 50 by 50 foot square. You can fit a total of 100 medium-sized creatures into this square. If occupying more than one square, a combat group can take any shape on the field, as long as all its used squares a connected. A Battle Round And this is how a single combat round is executed during a battle: 1. Rolling Initiative At the beginning of the battle round, an initiative roll is made to determine the order in which actions will be executed.

4 2. Ranged Attacks Next, all groups may perform their ranged attack modes if applicable. 3. Movement Phase Then, all combat groups may execute their movement. As stated above, every group is as fast as its slowest member. 4. Melee Attacks After movement, all groups perform their melee attack modes if applicable. Magic in Battle In many settings, magic is used in battles. In mass combat, offensive spells are just another attack mode. For example, treat a magic missile spell just as any other ranged weapon (except that no attack roll has to be made). Damage Causing Area Effect Spells When area effects are concerned, a few more factors have to be taken into consideration, though. Start by determining the average amount of damage the spell is going to deal. To determine the effectiveness of an area effect spell, first see how many 5 foot squares the spell can cover. For each square covered beyond the first, the spell can potentially hit one more group member. To reflect this, add one point of damage to the spell's average damage for every square covered beyond the first. For every spellcaster casting the spell beyond the first, a penalty of 1 is applied the opponent group's saving throw against the spell. Other area of effect spells Area of effect spells that cause no damage but have other effects are likewise handled by the extent of the area affected and limited by the total number of individuals in the opponent's group. For damage-less area of effect spells determine the number of creatures one caster can hit with it, then multiply this by the number of casters. If the result is lower than the number of creatures in the opponent's unit it has only half of its effectiveness. If the result is lower than half the number of creatures in the opponent's unit, it doesn't work at all. For every spellcaster casting the spell beyond the first, a penalty of 1 is applied to the opponent group's saving throw against the spell. Improvising These simple rules for converting the effects of spells to the battlefield do not always produce logical effects in practice. However, the GM may allow them to be used in this fashion regardless or she may alter the spell's exact effect in mass combat situations appropriately. For example, a group of 10 wizards of 6 th level decide to cast a fireball into another battle group. A fireball deals 1d6 damage per caster level, placing the average base damage for a single wizard at 21. A fireball covers about 52 squares of a standard combat field, thus adding another 51 to the base damage, resulting in a 72 total. This makes for an interesting 72 group damage score. (Save for half, but still...) Please note that this bonus damage for area effect spells cannot exceed the number of members in the opponent's group!

5 Group Combat Cards Individuals in Battle Casualties A Name: lost FSP always represents Ini.: a number of groups AC: members who are down (by corresponding hit points). Members: Refl.: Will: This primarily means those members cannot participate in Movmt.: combat anymore Space.: and are Fort.: left behind if Morale: the group moves Leader: away from its location. FS: Attack#1: GD: However, depending on the type and severity FSP:10 of damage Attack#2: received, it is unlikely GD: those creatures FSP: are 9 all dead. As as matter of the GM's discretion the state of Attack#3: GD: FSP: 8 those individuals can be decided by making a successfull Attack#4: fortitude saving throw GD: against as FSP: save 7 DC as high Feats/Special as 10 plus Abilities: the points of damage received per FSP: 6 individual during the last attack. FSP: 5 Notes: FSP: 4 FSP: 3 FSP: 2 FSP: 1 FSP: 0 Name: Ini.: AC: Members: Refl.: Will: Movmt.: Space.: Fort.: Morale: Leader: FS: Attack#1: GD: FSP:10 Attack#2: GD: FSP: 9 Attack#3: GD: FSP: 8 Attack#4: GD: FSP: 7 Feats/Special Abilities: Notes: FSP: 6 FSP: 5 FSP: 4 FSP: 3 FSP: 2 FSP: 1 FSP: 0