At the beginning of combat, all creatures who are aware of the combat roll for initiative. This is a d20 roll with an initiative modifier (Dex modifier + any miscellaneous bonuses) added. If some creatures are not aware that combat has begun, they don’t make this roll yet, and each other creature takes one turn in initiative order, highest first. This is known as the surprise round. Once this is done, the remaining creatures make their initiative rolls and combat continues in initiative order. Until a creature has taken an action, i.e., had their first turn, it is considered flat-footed. This means that it does not benefit from its Dexterity bonus or any dodge bonus to its SD.

Each round represents 6 seconds in the game world; there are 10 rounds in a minute of combat. A round normally allows each character involved in a combat situation to act. When the rules refer to a "full round", they usually mean a span of time from a particular initiative count in one round to the same initiative count in the next round. Effects that last a certain number of rounds end just before the same initiative count that they began on.

In a normal round, you can perform a standard action and a move action, or you can perform a full-round action. You can also perform one swift action and one or more free actions. You can always take a move action in place of a standard action or one or more swift actions in place of a move action at GM discretion.

In some situations (such as in a surprise round), you may be limited to taking only a single move action or standard action. Such decisions are to be made by the GM on a case-by-case basis, using the principle that a full combat round lasts six seconds.[https://docs.google.com/document/d/18WVXmcnlkfZtP711uP5BbB9BgxKSMKWbOpPWiaOX6jA/edit]

Standard A standard action allows you to do something, most commonly to make an attack or cast a non-attack spell. Some combat options (such as using the Spell Arc feat) are standard actions that allow you to make an attack, but don't count as the attack action. These options can't be combined with other standard actions or options that modify only attack actions (such as Know the Enemy). One of the most common standard actions is the attack action, which allows you to make a single attack at your highest base attack bonus, plus any other bonuses, penalties, or other effects that apply.

Move Despite the name, move actions include many options, including moving up to your speed. Other actions that can be taken in place are ones that take a similar amount of time, such as drawing a wand or standing up from prone.[https://docs.google.com/document/d/18WVXmcnlkfZtP711uP5BbB9BgxKSMKWbOpPWiaOX6jA/edit]

Full-round As made clear by the name, these actions take up a character’s entire turn. Many full-round actions will be those granted by feats, but once a character’s BAB reaches +6, she may use the full attack action, which allows her to make an additional attack for every +5 by which her BAB exceeds +1. Each successive attack is rolled at a lower BAB, according to a character’s class table. When making a full attack, a maximum of one of the spells cast may be a non-projectile spell.

Free Free actions are those that either require virtually no time at all to complete or can easily be done while performing other tasks. These include, but are not limited to, speaking, dropping an item, and ceasing concentration on a spell.[https://docs.google.com/document/d/18WVXmcnlkfZtP711uP5BbB9BgxKSMKWbOpPWiaOX6jA/edit]

Swift Swift actions are similar to free actions in that they do not limit your ability to perform standard and move actions, but you are only allowed one per round. Swift actions are primarily granted by feats, such as No Stranger to Misfortune. Other actions may be deemed swift at GM discretion.

Fight Defensively Standard/Full-round When attacking as a standard or full-round action, choose the fight defensively action to take a -4 penalty on all attack rolls for a +2 dodge bonus to SD until the start of your next turn.[https://docs.google.com/document/d/18WVXmcnlkfZtP711uP5BbB9BgxKSMKWbOpPWiaOX6jA/edit]

Ready an Action Standard You can ready any standard, move, or free action on your turn to use at any point before your next turn. When you ready an action, you must describe conditions that will cause your readied action to trigger. For example, “If an enemy enters range of my Stupefy, I will cast it targeting him.” When your action triggers this way, your turn in turn order is placed just before the turn of the creature whose turn you just interrupted.

Delay Action None, see text You may choose to delay your entire turn until a later initiative count. You do not have to choose in advance how far you want to delay your turn, but you must choose to take your turn after another creature has finished its turn, not during. Once you take a delayed turn, that becomes your turn in the initiative order.

Players familiar with D&D or Pathfinder will be acquainted with attacks of opportunity, free melee attacks made out of turn in response to a gap in an opponent’s defenses. As melee attacks are not a core part of this rulebook as such, attacks of opportunity will not be detailed here. However, groups wishing to incorporate melee combat into their campaign may feel free to use existing rules for attacks of opportunity from D&D or Pathfinder. Unlike spellcasting in D&D, spells cast in this system do not provoke attacks of opportunity.

Every creature has a Spell Defense, which is one of the most important characteristics in combat. Spell Defense, or SD as it will be referred to hereafter, represents how hard it is to hit or affect a creature with a spell. The number of a creature’s SD is the number that attackers need to roll in order to hit it, so a higher SD implies that the creature is harder to hit. A creature’s SD is determined by a number of factors, including, but not limited to, its Dexterity, its size, its class, feats, magical properties of the creature, spell effects, status effects, and special actions in combat. The formula for SD is 10 + Dexterity modifier + size modifier + natural spell resistance + class SD bonus. Humans, and therefore all player characters, receive no size modifier or natural spell resistance. Another term that will often come up is Flat-footed SD. Flat-footed SD is just like SD, except that it doesn’t include a creature’s Dexterity modifier, and is the number attackers need to roll if their target is unable to properly react or dodge as they normally would. This occurs in several situations, including if the target has not yet had their first turn in combat, or if the attacker is successfully hidden from their target. These are not the only exclusive situations in which flat-footed SD will be used, and the GM may declare instances as they see fit.

When in combat, more often than not you will find yourself and your enemies fighting from behind cover. Different types of cover provide different benefits, but the main purpose they serve is simple: making yourself harder to hit, or giving yourself a higher SD. Examples of cover may be a 3 foot high wall, fighting from behind a tree in a forest, casting spells out of a window, or even through a wall with one brick removed. Not all cover provides the same benefits, and the following table may be referred to in order to determine the benefits of whatever cover you may find in your campaign.

Just because you are in cover does not mean that you are impossible to hurt. Some cover is destroyable, meaning that it can be removed from play. Take a wooden fence for example. While it may provide your character with decent cover, if an enemy knows you are there they may take other actions to get to you. A foe could cast Reducto at the fence, which is incredibly easy to hit and rather fragile. This explosion could easily destroy the fence, dealing minor damage to you, but more importantly leaving you now completely exposed. In the context of this game, cover, even long objects like fences stretching hundreds of feet, will be dealt with as separate, 5-foot-long sections. No matter its height or length, a character wishing to destroy an object targets a 5-foot section of it (or 25-square-foot section, if it is taller than 5 feet). If this section is destroyed, the GM can determine whether other sections (or other objects entirely) are affected by whatever destroyed the first one. For example, if a character deals 30 damage to a 5-foot section, which has around 10 hit points, the GM may decide that the blast is powerful enough to destroy the sections on either side of the targeted one.

Cover may be hit by a spell even if it is not the intended target. If you target a character behind cover with a damaging spell and your attack roll misses the target’s SD by a number less than or equal to the SD bonus granted by the cover, the cover is hit instead for half damage. [https://docs.google.com/document/d/18WVXmcnlkfZtP711uP5BbB9BgxKSMKWbOpPWiaOX6jA/edit]

The following table may be referred to in order to determine SDs and hit points of various forms of cover. If a cover’s hit points are reduced to zero, it is then considered ineffective and does not provide a cover bonus to its defender’s SD. At half of its starting hit points, it’s cover bonus to the defender is reduced by half.

To determine whether your target has concealment from your ranged attack, choose a corner of your square. If any line from this corner to any corner of the target's square passes through a square or border that provides concealment, the target has concealment.[https://docs.google.com/document/d/18WVXmcnlkfZtP711uP5BbB9BgxKSMKWbOpPWiaOX6jA/edit]

Concealment gives the subject of a successful attack a 20% chance that the attacker missed because of the concealment. Make the attack normally—if the attacker hits, the defender must make a miss chance d% roll to avoid being struck. Multiple concealment conditions do not stack.[https://docs.google.com/document/d/18WVXmcnlkfZtP711uP5BbB9BgxKSMKWbOpPWiaOX6jA/edit]

If you have line of effect to a target but not line of sight, he is considered to have total concealment from you. You can't attack an opponent that has total concealment, though you can attack into a square that you think he occupies. A successful attack into a square occupied by an enemy with total concealment has a 50% miss chance (instead of the normal 20% miss chance for an opponent with concealment).

Concealment isn't always effective. An area of dim lighting or darkness doesn't provide any concealment against an opponent with darkvision. Characters with low-light vision can see clearly for a greater distance than other characters with the same light source. Although invisibility provides total concealment, sighted opponents may still make Perception checks to notice the location of an invisible character. An invisible character gains a +20 bonus on Stealth checks if moving, or a +40 bonus on Stealth checks when not moving (even though opponents can't see you, they might be able to figure out where you are from other visual or auditory clues).

When making an attack, roll at advantage if your opponent is in at most medium spell range of another enemy character or creature on its opposite border or opposite corner. This other creature must be hostile to your target but need not be your ally.[https://docs.google.com/document/d/18WVXmcnlkfZtP711uP5BbB9BgxKSMKWbOpPWiaOX6jA/edit]

When in doubt about whether two characters flank an opponent in the middle, trace an imaginary line between the two attackers' centers. If the line passes through opposite borders of the opponent's space (including corners of those borders), then the opponent is flanked.[https://docs.google.com/document/d/18WVXmcnlkfZtP711uP5BbB9BgxKSMKWbOpPWiaOX6jA/edit]

When a character makes an attack with a Jinx, Hex, Curse, or spell from any other school that deals damage (these will often be referred to as projectile spells), she makes an attack roll. Attack rolls are also required for non-damaging spells that are neither Jinxes, Hexes, nor Curses if the target is behind half-cover or greater or has concealment, but natural 20s on these rolls do not provide any additional effect beyond the automatic hit. Attack rolls are always d20 rolls. She adds her attack modifier to the result. If the total equals or exceeds the target’s SD, the attack hits. The attack modifier is equal to base attack bonus (BAB) + the character’s Dexterity modifier. Base attack bonus is determined by class and increases with level.

Any spell that deals damage has its damage dice indicated in its description. If one of these spells hits a target, the caster rolls the indicated damage dice. If that spell is a Ferocity spell, the caster may also add a modifier. If the caster is proficient in the school of a damaging Ferocity spell she casts, she adds her Might modifier, if positive, to the damage roll (this is the standard school proficiency bonus for Ferocity). However, if the caster is not proficient in the school of a damaging Ferocity spell she casts, she adds her Might modifier, if negative, to the damage roll.

When a character rolls a natural 20 (the d20 comes up on a 20 before any modifiers) on an attack roll, the attack automatically hits. If the spell is a projectile spell (see Attack Rolls and Attack Modifier above), it is a critical hit. If the spell deals any amount of damage, roll your normal damage twice. For example, if you would normally roll 1d8 + your Mig modifier, instead roll 2d8 + twice your Mig modifier.

If the spell does elemental damage (fire, cold, electric), it gains bonus effects on a critical hit if the target fails an additional Fortitude save. These debuffs don’t stack multiple times on the same creature if it is hit by multiple critical hits, but the duration can be extended if the duration roll for the new crit is higher than the current remaining rounds.

When a character rolls a natural 1 on an attack roll with a projectile spell, the attack automatically fails to hit its intended target and hits the caster instead. If that spell requires a save, the save is rolled at disadvantage.[https://docs.google.com/document/d/18WVXmcnlkfZtP711uP5BbB9BgxKSMKWbOpPWiaOX6jA/edit]

There are two kinds of shield spells: those that target and deflect incoming spells, and those that create a barrier around the caster that has hit points and can be destroyed. For the remainder of this section, the former will be referred to as targeting shield spells, and the latter will be referred to as static shield spells.

Targeting shield spells typically have “Protego” in the incantation. A character can prepare a targeting shield spell on her turn and cast it in response to an enemy’s spell. She must choose to cast the shield spell as the targeted spell is being cast, and therefore does not know what the targeted spell is unless she first makes a Spellcraft check, as an immediate action, to identify the spell as it is being cast. The character casting the shield makes an attack roll but adds her Con modifier instead of Dex. If the targeted spell did not require an attack roll, its caster rolls one now. If the attack roll of the shield exceeds that of the targeted spell, the targeted spell is negated. If it also equals or exceeds the SD of the character who cast the targeted spell, it is reflected back at them. It is still treated as the original caster’s spell for the purposes of damage rolls and save DCs.

Static shield spells create magical barriers that cannot be penetrated by most spells cast by enemies of the caster. Static shields have hit points and are destroyed when their hit points are reduced to 0. The caster must maintain the shield spell each turn as a full-round action by succeeding on a concentration check of DC 10 + the spell level or else it immediately dissipates. Other things equal, static shields have fewer hit points and lower SD the larger they are.

Some spells, such as those that require maintenance each round, require concentration from the caster, as listed in the spell description. Sometimes concentrating is simply at will, but on some occasions a concentration check is required. A concentration check is a d20 roll with the caster’s level and governing attribute modifier added. The following table details some of the situations that require concentration checks.

A character may choose to cast any spell non-verbally. This decision must be announced before the spell is cast. To successfully cast a spell non-verbally, you must make a concentration check, by rolling a d20 and adding your level and governing attribute modifier. The DC of the concentration check is equal to 15 + double the spell level. If you fail the check, you lose the spell. If you succeed, the spell is cast silently (other effects of the spell that would cause noise, such as interactions with the environment, are not silenced). A stealthed character that successfully casts a non-verbal spell does not break her stealth as she would otherwise. A spell cast non-verbally increases the DC of Spellcraft checks made to identify it as it is being cast by 15. If a character attempts to target a spell cast non-verbally with a spell such as Protego, the attack roll of the non-verbal spell that the targeting spell must beat is treated as 2 higher.

If a creature is to be affected by a spell that has a harmful effect other than damage, it makes a saving throw. The particular save is noted for each spell in the Save column. If the creature fails the save, it receives the full effects of the spell. If it succeeds, it negates (or reduces, in the descriptions of some spells) any effects other than damage.

Spells that deal splash damage deal the full indicated damage to the target, or half damage on a successful Reflex save. Creatures and objects adjacent to the target take half damage, or no damage on a successful Reflex save. These spells do not need to target a creature and can target inanimate objects or even floors and walls. When targeting a floor or wall, you may choose a specific grid intersection with SD 5.

If your attack misses, the spell could go in one of eight directions. A 3x3 vertical grid is placed around the target perpendicular to the direction of the spell being cast with the target in the center. Numbers 1-8 are assigned to each grid space surrounding the target, with 1 being assigned to the square below the target and the rest distributed clockwise on the grid. 1d8 is rolled to assign the direction in which the missed spell will travel. Once the direction is assigned, a straight line may be imagined traveling through the center of the assigned square through which it will continue until the spell hits an object dealing its normal damage, or until it reaches its maximum range at which point the spell dissipates. [https://docs.google.com/document/d/18WVXmcnlkfZtP711uP5BbB9BgxKSMKWbOpPWiaOX6jA/edit]