HD&D: Combat Modifiers

[Index to the Combat System]

Battles aren’t fought on a flat featureless terrain where enemies stand toe to toe and simply slug it out until one falls over. There are countless other little things that characters can do to try and give themselves temporary advantage while in combat. Archers might bed down behind cover so they can attack their enemies, without their enemies being able to attack them. You might gang up or flank your opponents. You might always try to attack from the high ground, or on horseback.

Combat Modifiers are situational bonuses and penalties that most usually apply to a character’s attack rolls or Reflex defence. Seek these out in combat. Gods know you need all the advantages you can get! The following tables summarise the most common combat modifiers:

Circumstance Modifier to Attack Roll
Broken weapon or item -2
Combat Advantage +2
Dazzled -1
Exhausted -5
Fatigued -2
Frightened -2
Grappled -51
Panicked -2
Prone -2
Shaken -2
Sickened -2
1 Except checks made to grapple, or escape from a grapple.


Circumstance Modifier to Reflex Defence
Blinded -5
Concealment +2
Concealment (Total) +5
Cover +4
Cover (Superior) +8
Cowering -21
Exhausted -51
Fatigued -21
Frightened -21
Grappled -5
Panicked -21
Pinned -5
Prone +22
Shaken -21
Sickened -21
1 This modifier also applies to Fortitude and Will defences.
2 Modifier is -2 against mêlée attacks

Combat Advantage

One of the most common combat modifiers (and certainly the one that is mentioned the most) is Combat Advantage. Combat advantage represents a situation where the defender cannot give his full attention to the danger at hand. He might be pressed by multiple foes at the same time, or he might be surprised or stunned or otherwise distracted.

If you have Combat Advantage over a target then you have +2 bonus to your attack rolls against that target. However, this measily +2 does not convey quite how much an advantage combat advantage is for some characters.

Numerous feats, talents and spells key off combat advantage. They don’t work unless you have combat advantage over your foe. A rogue’s sneak attack is the most obvious example of this. If the rogue has combat advantage he inflicts a bucketful of extra damage dice. If he hasn’t then he doesn’t.

Seek out the benefits of Combat Advantage if you can. Even that “measily” +2 to hit can swing a battle one way or another. The more astute combatants will try to avoid reckless tactics that grant combat advantage to their enemies. Of course, this may not always be possible.


Taking cover is often the best way of avoiding ranged weapons, spells and mêlée attacks aimed at you. Cover is a tangible barrier that is inbetween you and harm. You might duck down beneth a low wall, hide behind a tree or duck back behind a corner. If you have cover, your enemies take a penalty on their attack rolls to hit you.

Cover is divided into three categories: Cover, Superior Cover and Total Cover. These categories reflect the increasing degrees of protection provivded by the terrain:

Cover: You gain cover from anything that obscures a quarter of your body or more. Standing at an open window, or behind a tree or around a corner provides cover. If you have cover, then you enjoy a +4 bonus to your Reflex defence against all attacks. Opponents still have line of sight and light of effect to you if you have cover.

Superior Cover: You gain superior cover from anything that obscures more than three-quarters of your body. Peering around a corner, standing at an arrow slit or behind a door that is slightly ajar will grant you superior cover. If you have superior cover, then you have a +8 bonus to your Reflex defence against all attacks. This doesn’t stack with the bonus provided by standard cover. Opponents still have line of sight and light of effect to you if you have superior cover.

Total Cover: If you are completely obscured from view by a solid object then you have total cover. Standing on the other side of a stone wall, inside a wagon or down a deep hole may grant you total cover. If you have total cover then you cannot be attacked. Although attacks can be directed at the cover that is protecting you. Opponents do not have line of effect to you if you have superior cover; they probably don’t have line of sight either (unless you’re hiding behind a transparent barrier).

Creatures and Cover: If you are engaged in mêlée combat, then your opponents and your allies provide you with cover against ranged attacks made against you, but not against mêlée attacks, close attacks or far attacks. See Firing into Mêlée (q.v.) for more informaiton on this.

Destroying Cover: If an opponent cannot hit you because of your cover, then they can target the cover instead. Details for substance and item AC and hit points can be found in the Equipment section. If an attack deals sufficient damage to destroy the cover you are hiding behind, then you take the remaining damage (assuming the attack roll was high enough to hit you).

Cover and Concealment: Bonuses to your reflex defence granted by cover and concealment stack.


Where cover represents a physical barrier between you and your enemies, concealment is an intangible barrier. Darkness, fog, heavy rain or a blizzard may give you concealment from your enemies. If they can’t see you properly, then they have a much harder time targeting you with their attacks.

Unlike cover, concealment only provides protection from attacks that target individuals – i.e. Mêlée and Ranged attacks. Any attacks that affect all or some indviduals within a certain area ignore concealment. It doesn’t matter where in the blast radius of a fireball you enemy is standing, as long as he is standing somewhere in the blast radius. See the Line of Sight rules (q.v.) for guidance on trying to pinpoint the location of concealed characters.

Concealment is divided into two categories that reflect deepening degrees of imperceptibility:

Concealment: If you have concealment, then your opponents find it more difficult to pinpoint where you are standing. Conditions of dim light, heavy foliage, heavy snowfall, smoke or fog grant you Concealment. If you have concealment then you gain a +2 bonus to your Reflex Defence against mêlée and ranged attacks. Opponents still have line of sight and light of effect to you if you have concealment.

Total Concealment: A character with Total Concealment cannot be seen at all. Invisible characters (q.v.) are considered to have total concealment, as is anyone standing in total darknes, in a pea soup fog or similar intangible protection. If you are blind, then everyone has total concealment from you all the time. If you have Total Concealment then you gain a +5 bonus to your reflex defence againt mêlée and ranged attacks. Opponents still have line of effect to you if you have total concealment, but they do not have line of sight to you.

Concealment and Cover: Bonuses to your reflex defence granted by concealment and cover stack.


One of the simplest combat tactics is for you and an ally to move into a flanking position. Flanking works because you and your ally stand on opposite sides of the same target, and both attack that target. Because the foe cannot devote his full attention to either you or your ally, he grants combat advantage to you both.

In game terms, if you are engaged in mêlée combat and you also outnumber your foes by a ratio of 2:1 then you are considered to be flanking those foes. Basically, if you mob your opponent, then you gain an advantage over him. Flanking is a particularly potent manoeuvre if the entire party is attacking the same foe – which often happens in battle against massive monsters such as dragons or purple worms.

When Flanking Fails: You can only flank if you are engaged in mêlée combat. Allies attacking the same foe from range cannot aid in flanking, nor do they enjoy combat advantage over the target. Additionally, characters that are Blinded, Dazed, Stunned or suffering any condition that prevents it from making normal attacks cannot contribute to flanking a target. Creatures with a Reach of 0 (notably diminuitive and miniscule creatures, or swarms) are unable to flank.

Situational Modifiers

There are a vast number of options in combat, and no set of rules can hope to cover them all. As with the rules to skills, the GM is well within his rights to impose situational modifiers to certain situations if he feels the outcome of a certain event is skewed in the direction of success or failure.

These modifiers are always Circumstance Modifiers, and usually they will be a modest +2 or -2 to a skill check or defence, although could be more extreme if the situation warranted. The GM should impose the situational modifiers sparingly, and should be careful that he is not penalising the PCs twice by saddling them with two different penalties to the same activity.

If a circumstance has the effect of improving or diminishing a character’s chance of success (e.g. the character is vomiting uncontrollably) then the modifier should apply to the character’s skill check.

If a circumstance has the effect of making a character easier or trickier to target with an an attack (e.g. they are wearing a luminous balaclava) then the modifier should apply to the characters defence.

For example: the PCs have broken into a museum in the dead of night with the hope of acquiring a magical urn that is currently on display. The urn has special properties that will contain the ashes of a master vampire. The pick up the fragile urn, but are jumped by the museum guards. Now they must fight and keep the urn intact. The GM rules that whoever is carrying the urn takes a -2 penalty to attack rolls and Reflex defence because they are trying to stop the object from getting broken.

Size and Combat

A creature’s size may affect its combat statistics. Only characters of Small or Medum size do not have these modifiers. All other creatures will find their attack rolls, reflex defence and hit points modified by their bulk. These effects are summarised in the following table:

Creature Size




Miniscule +6 +6 1
Diminuitive +4 +4 1
Tiny +2 +2 2
Small 0 0 4
Medium 0 0 4
Large -2 -2 8
Huge -4 -4 12
Gargantuan -6 -6 16
Colossal -8 -8 20

The modifiers to attack rolls only apply to mêlée combat using weapons, natural weapons or unarmed attacks; and to ranged combat using thrown weapons such as axes, hammers and javelins.

Fortunately, these are the sort of modifiers that you only apply once during character generation and can then promptly forget about. Some racial traits and talents may mitigate some of these penalties. Don’t assume all colossal creatures are slow and easy to hit.

A creature’s size can also have a more immediate effect in combat. Questions of how many monsters can mob or attack a character at the same time are fairly common. In these circumstances, GMs need to bear the following principles in mind.

Assuming sufficient space, a creature can be attacked by up to four different creatures of the same size in the same combat round. Obviously, they can be attack by fewer larger foes, and more smaller foes.

Although Small and Medium creatures follow the same rules in most circumstances, they are still different size categories. Different rules govern the types of weapons these characters can wield, and different rules govern how they are reated here/ Each size category less than Medium, or greater than Medium, equates to a decrease or increase in the size of a creature by a factor of two.

Therefore a Large creature is twice the size of a Medium creatue. A Huge creature is twice the size of a large creature, and therefore four times the size of a Medium creatures and so on and so forth. This isn’t an accurate assessmnet of a being’s dimensions in the real world, but it is a handy shorthand for juggling how many creatures of a certain size can be in a given space at the same time.

The following table summarises the number of creatures (of different sizes) that could beseige small, medium or large PCs. in the same combat round:

Creature Size

Small PC

Medium PC

Large PC

Miniscule Many Many Many
Diminuitive 16 Many Many
Tiny 8 16 Many
Small 4 8 16
Medium 2 4 8
Large 2 2 4
Huge 2 2 2
Gargantuan 2 2 2
Colossal 2 2 2

Therefore eight small sized creatures could attack a medium-sized human in one round, but sixteen could get close enough to make an attack on a large ogre. When considering how many PCs can mob an enemy, then simply invert the table:

Creature Size

Small PC

Medium PC

Large PC

Miniscule 2 2 2
Diminuitive 2 2 2
Tiny 2 2 2
Small 4 2 2
Medium 8 4 2
Large 16 8 4
Huge Many 16 8
Gargantuan Many Many 16
Colossal Many Many Many

So up to sixteen large wyverns could surround and attack a gargantuan dragon in the same round. Remember that each increase in size category represents a doubling in size. This means that one Large creature counts as two medium creatures. Therefore fifteen wyverns and two dwarves could attack that dragon at the same time.

If the difference in size category between the attacker and the target is three of more, then this sort of comparisson breaks down. Do we really need figures to suggest how many humans can attack a 200 foot dragon, or how many wasps can attack a human? In these cases the tables simply state “Many”. It’s up to the GM to fairly adjudicate if these conditions arise. Chances are he’ll chose to use the swarm rules instead.

Equally, regardless of your size in relation to your target, a minimum of two foes can attack a target in the same round. So two colossal red dragons can attack the same bluebottle in the same round if they choose to.

Types of Modifiers

In HD&D you will find that some of the modifiers (penalties and bonuses) that you ally to your attack rolls are given a name, and some are not. Named modifiers tell you how your character has gained this bonus to his actions. For example, you gained a morale bonus from being inspired and generally cheered up.

Two bonuses of the same type do not stack. if you have two bonuses of the same type, then you take the higher bonus. For example, if you are carrying a heavy shield (which provides a +2 deflection bonus to your reflex defence) and a wizard casts the shield spell on you (which provides a +4 deflection bonus to reflex defence) then you only have a +4 deflection bonus to reflex defence, not +6.

A bonus and a penalty of the same type will still work against one another and perhaps cancel one another out. If you bard is singing an inspiring song that grants you a +2 morale bonus to your attack rolls, and the enemy bard is singing a depressing dirge that imposes a -2 morale penalty to attack rolls then the net effect is to give you a morale modifier of +0.

Untyped bonuses stack with anything. Talents, spells or feats that provide these bonuses will stack with every other bonus, but they are still not cumulative with themselves. A masterwork longsword might grant you a +1 bonus to attack rolls, but you can’t gaffer-tape two of them together and claim a +2 bonus.

The rules for modifier types do not just apply to attack and damage rolls in combat. Situational modifiers can apply any time you pick up and roll a die. Sometimes the modifier will be of one of these listed types; sometimes it will be an untyped bonus. The use of such modifiers, and when to apply them, is left to the discretion of the GM.

The number of modifier types have been kept deliberately small for the hybrid game. These are the types of modifiers you may come across in the combat and beyond:

Armour: Usually only expressed as a bonus, the armour modifier applies to your characters Armour Class. It is granted by manufactured armour (such as chain, hide, plate and so on) or by spells or magical effects that mimic armour. Armour will stack with Natural Armour bonuses, but two Armour bonuses from different sources will not stack.

Circumstance: A circumstance modifier arises from special conditional factors that impact on the success of the task at hand. Trying to pick a lock with masterwork lock-picks grant you a +2 circumstance bonus to your Disable Device skill check.

Competence: These bonuses and penalties reflect an intrinsic (put usually temporary) alteration in your character’s skill at any paricular task. For example, bards have the ability to Inspire Competence which temporaily makes a character more skilled at a particular task than he otherwise would have been. Competence modifiers usually only apply to skill checks, saving throws or defences.

Deflection: Usually expressed as a bonus, deflection modifiers almost always apply to you character’s Reflex defence. They represent the presence of a character-controlled barrier that can be brought to bear to repel attacks. The barrier doesn’t prevent penetrative damage (it’s not armour), it’s designed to turn aside attacks. Certain magical fields of protection, and the humble shield both grant deflection bonuses to characters.

Enhancement: An enhancement bonus (there are no enhancement penalties) is a continuous advantage to your character that is granted by an outside source. A magic ring may, for example, grant a +1 enhancement bonus to all your defences for as long as it is worn. A Firewalker’s Regalia of Consummate Funk may provide a +2 damage bonus to all spells with the Fire description. A magic sword may grant a +1 enhancement bonus to attack and damage rolls. Unlike circumstance bonus, enhancement bonuses tend to be magical in origin although this is not always the case. Enhancement bonuses are lost if you lose the item that grants them to you.

Inherent: An inherent bonus (or penalty) is something that comes from within you. If you take a feat or talent that grants you an inherent modifier then you are making a permanent change to your character. Feats such as Weapon Focus or Iron Will grant inherent bonuses to your attack rolls or defences in certain circumstances. No-one can take an inherent bonus away from you, once you have one it’s yours for life.

Morale: A morale bonus represents the effects of greater hope, courage and determination; while morale penalties induce a sense of hopelessness, cowardice and despair. Creatures without an Intelligence score cannot benefit from morale bonuses.

Natural Armour: This is a bonus to armour class derrived from a thick hide, scales or other uber-dermal protection. A stone golem has a high natural armour because he’s made of stone. Natural armour bonuses stack with armour bonuses.

Racial: These bonuses derrive from your race or heritage. For example, some elves have a +2 racial bonus on Perception checks.

Size: All creatures that are not classed as Small or Medium have size modifiers that apply to certain attack rolls, reflex defence and hit points. Size modifiers do not stack with one another. If a creature changes size, then the size modifier for the next size category applies.


All these rules, and I still haven’t told you how your character gets from A to B. Friday’s update is Movement in Combat.

One thought on “HD&D: Combat Modifiers

  1. Critique

    The biggest change you will probably notice between HD&D and Third Edition are the rules for Concealment. In third edition concealment gave you a miss chance. Someone with Total Concealment had a 50% miss chance, meaning that every time they were successfully hit the player rolled percentile dice and on a roll of 51-00 the hit was negated. Pretty simple stuff, so why throw it out?

    Well, a percenitle roll never really struck be as in keeping with the rest of the d20 system. It’s also frustrating for players to have the rush of scoring a hit on their foe, only to find out that they actually didn’t hit at all. HD&D uses the same rules as 4e. Concealment imposes a penalty to hit. What this means is something that has both cover and concealment is really, really difficult to hit… but shouldn’t that be the case?

    I also wanted to say something about the Types of Modifiers in the game. Rules of this sort have been around since the early days of third edition. It’s obviously handy to have rules like this, because if everything stacks with everything else a judicious selection of feats and talents could create a demigod by seventh level. However, HD&D does things a little differently to its predecessors. Here are the modifier types from the last two editions:

    Third Edition: Alchemical; Armour; Circumstance; Competence; Deflection; Dodge; Enhancement; Inherent; Insight; Luck; Morale; Natural Armour; Profane; Racial; Resistance; Sacred; Shield; Size.

    Fourth Edition: Armour; Enhancement; Feat; Item; Power; Proficiency; Racial; Shield.

    Third edition classified bonuses by their effect, while 4e classified bonuses from their most prosaic source. That’s fourth edition for you. In creating HD&D I wanted to classify bonuses in a similar manner to third edition, but I wanted significantly less types of bonuses. I think I’ve managed to succeed there. I’m pleased with distinction that an “enchancement bonus” in HD&D is something granted to you by an outside agent like a magic item or a spell, while an “inherent bonus” is something you’ve done to permanently change your character – like a feat or a talent.

    As always, let me know your thoughts.

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