Aerial & Underwater Combat

Aerial Combat

Aerial combat is much different from ground-based combat. For one thing, falling or being knocked from one's mount means a long fall to the ground, usually resulting in death. For another, combatants have to think in three dimensions, not just two – opponents can (and often do) attack from above or below as well as from the sides, front, or rear. As with groundbound combat, a creature with a higher position gains a +1 bonus to attack rolls against those below it, and those in a lower position suffer -1 to attack rolls against those above.

Ranged Combat: Flying creatures are almost always in motion, which makes them harder to hit. Ranged attacks against a flying creature suffer a -2 penalty, or -4 if it is moving at double speed, or -6 for triple speed (applies only during a dive). This rule can be applied to any moving creature, whether in the air or on the ground, at the DM's option.

Similarly, those trying to use ranged weapons from the back of a flying mount (to include a broom/carpet of flying) suffer -2 to their attacks if the mount is making a normal move, or -4 if the mount is making a double move. Ranged attacks are not possible during a dive.

Spellcasting: Spellcasting from the back of a flying mount is little different from a ground-based one, but since the mount is (generally) constantly moving so as to maintain flight, a Concentration check is always required. Certain magic items, like carpets of flying, provide stable platforms for spellcasting, as they can stop and hover.

Tactical Aerial Movement

Once movement becomes three-dimensional and involves turning in midair and maintaining a minimum velocity to stay aloft, it gets more complicated. Most flying creatures have to slow down at least a little to make a turn, and many are limited to fairly wide turns and must maintain a minimum forward speed. Each flying creature has a maneuverability, as shown on Table 1: Maneuverability. The entries on the table are defined below.

Table 1: Maneuverability

Perfect Good Average Poor Clumsy
Minimum forward speed None None Half Half Half
Hover Yes Yes No No No
Move backward Yes Yes No No No
Reverse Free -5 ft. No No No
Turn Any 90º/5 ft. 45º/5 ft. 45º/5 ft. 45º/10 ft.
Turn in place Any +90º/-5 ft. +45º/-5 ft. No No
Maximum turn Any Any 90º 45º 45º
Up angle Any Any 60º 45º 45º
Up speed Full Half Half Half Half
Down angle Any Any Any 45º 45º
Down speed Double Double Double Double Double
Between down and up 0 0 5 ft. 10 ft. 20 ft.

Minimum Forward Speed: If a flying creature fails to maintain its minimum forward speed, it must land at the end of its movement. If it is too high above the ground to land, it falls straight down, descending 150 feet in the first round of falling. If this distance brings it to the ground, it takes falling damage. If the fall doesn't bring the creature to the ground, it must spend its next turn recovering from the stall. It must succeed on a DC 20 Reflex save to recover. Otherwise it falls another 300 feet. If it hits the ground, it takes falling damage. Otherwise, it has another chance to recover on its next turn.

Hover: The ability to stay in one place while airborne.

Move Backward: The ability to move backward without turning around.

Reverse: A creature with good maneuverability uses up 5 feet of its speed to start flying backward.

Turn: How much the creature can turn after covering the stated distance.

Turn in Place: A creature with good or average maneuverability can use some of its speed to turn in place.

Maximum Turn: How much the creature can turn in any one space.

Up Angle: The angle at which the creature can climb.

Up Speed: How fast the creature can climb.

Down Angle: The angle at which the creature can descend.

Down Speed: A flying creature can fly down at twice its normal flying speed.

Between Down and Up: An average, poor, or clumsy flier must fly level for a minimum distance after descending and before climbing. Any flier can begin descending after a climb without an intervening distance of level flight.

Aerial Combat Maneuvers

Dive: The aerial version of the charge attack, and one used most often by flying creatures. In order to perform a dive attack, the attacker must be at least 30 feet above the target. A dive attack is a full-round action, just like a charge, but the attacker can move up to three times its base speed instead of twice, because gravity is helping it along. The attacker can make a single attack at +2, but it (and its rider, if it has one) suffers a -2 penalty to Armor Class. If the attacking creature has a rider, only the rider or the mount may make an attack – not both. As with a normal mounted charge, the rider deals double damage with a lance, and the benefits from the Spirited Charge feat apply to aerial mounts. Weapons like spears can be set to receive a dive, but only if the defender is on the ground.

If the creature has the Snatch feat, it can make a grab attack as part of the dive. In this case, if the grapple check succeeds, the target is considered grappled (see below), and the creature deals automatic damage each round, or can fling or drop it. Note that a mount can make a snatch attack, but not if its rider makes an attack as part of the dive – one or the other can act, but not both.

Grapple: An aerial grapple is only slightly different from a ground-based grapple. The main difference is that flying creatures often lose the ability to fly while grappling (see below), which means that aerial grapples are often very short – only a few rounds at most.

Conduct the grapple normally, but take these points into consideration:

  • Unlike ground-based grappling, the vast majority of grappling attacks come from a flanking position (usually above the target), which obviates a possible attack of opportunity. If the attack comes from elsewhere (from the front or below, for instance), then the grappler provokes an attack of opportunity from the target if applicable.
  • In an active grapple, unless one or both creatures have the ability to hover, the attacker is two or more sizes larger than the target (and not heavily encumbered), or it has grabbed something using the Snatch feat, both creatures lose the ability to fly (their movement rate is reduced to 0) and start to fall (see Falling, below). For example, a dragon with a human clinging to its back or in its claws can still fly, but two dragons of similar size locked in combat cannot. The exception to this rule is creatures who have innate or magical flight ability – beholders, air elementals, or someone using a fly spell – as they don't have to concentrate on staying aloft.
  • As with a normal grapple, the attacker can release its target at any time; if one or both are in freefall, they must make Reflex saves each round as noted under Falling.


Falling is the single greatest threat to an airborne creature, especially one without the ability to fly on its own. Under rare circumstances, a falling creature can land in an area that might break its fall, to the point where it suffers little to no injury. Such circumstances are ultimately up to the DM, but can provide a way to save unlucky PCs who fell through no fault of their own – bad die rolls, bad luck, etc., or to provide a warning to incautious players.

Contrary to popular belief, water will not break a fall – water has surface tension and does not compress like normal soil (the ground has a certain "give", whereas water doesn't), so falling onto water from a great enough height is just like falling onto stone. Even if a falling creature does somehow survive a fall into water from a great height, he still has to contend with drowning.

Trees are the best way to slow/break a fall – conifers (pines, firs, etc.) are the best among these, because they usually grow close together, and their branches point mostly downward, which means a falling body won't get caught on them. Deep snow is, obviously, also a good way to break a fall, as are thick bushes/brush, or mud (swamps), as opposed to water. Trees, brush, snow, etc. can reduce the damage from a fall by up to 90% (DM's discretion as to degree).

A falling flying creature requires a certain amount of space to recover; once it gets too close to the ground, however, it loses the chance to pull out of its fall, and it hits the ground. The table below shows the minimum distance a creature of a given size must be from the ground to be able to pull out of a fall or dive without actually hitting the ground.

Size Min. Dist.
Tiny and below 5 ft.
Small 10 ft.
Medium 15 ft.
Large 20 ft.
Huge 25 ft.
Gargantuan 30 ft.
Colossal 35 ft.
Titanic 40 ft.

Even if a creature is within the minimum distance, it can still attempt a DC 20 Reflex save to slow its fall slightly, taking less damage. The DC remains the same; if the save is successful, the creature takes 2d6 fewer dice of damage, plus 1d6 per 5 points by which its check result exceeds 20. In most cases, this won't matter, since the creature will likely die anyway, but it can help for shorter falls.

Falling Speed

Terminal velocity is around 165 ft./second. For game purposes, a falling object reaches terminal velocity on the third round – on the first round it reaches the 50% mark, or around 80 ft./second (500 feet); by the end of the second round, it's reached 99%, or around 160 ft./second (960 feet), and at the beginning of its turn on the third round, it's falling at 165 ft./second. This equates to…

First round: 480 feet (round to 500 feet);

Second round: 960 feet (round to 950 feet);

Third round+: 990 feet (round to 1,000 feet).

So a person falling from 5,000 feet would fall for five rounds and hit the ground on the sixth. If this were a flying creature, it could attempt to pull out of the fall during its turn on the sixth round instead.

It is possible to achieve speeds greater than terminal velocity – a skydiver in freefall position can fall up to 200 mph, as opposed to 120 mph for terminal velocity, by decreasing the amount of drag – but for purposes of this system, it's assumed that falling creatures are in that position unwillingly, and are thus not trying to fall faster.


Weather is, perhaps, the single biggest obstacle to flight, and by extension, aerial combat; high winds, heavy rain, and lightning can ground almost any creature besides an air elemental.

High Winds: See Weather for the effects of high wind on flying creatures.

Lightning: Lightning can (and does) strike flying objects, not just those one the ground; the only difference is that since flying creatures aren't grounded, they don't take as much damage – the current dissipates into the air instead of running through the object or creature into the ground. For game purposes, this means that all lightning strikes deal half damage automatically, and the target can make a Reflex save to reduce that to half again. Natural lightning deals 8d6 damage; any creature of Medium or larger size flying during a thunderstorm runs a chance of being hit by a lightning strike – 10% per minute, +5% per size category over Medium. A creature that fails its save must make a Fort save (DC 17) or be stunned for 1d3 rounds, which renders it temporarily unable to fly.

Rain: Rain impedes most creatures' ability to fly, especially birds, as it soaks their feathers, making them heavier, and the wings harder to move. The table below provides some guidelines for degrees of rainfall and what creatures are affected by it. Note that, as with wind effects, flying creatures are treated as being one size smaller than they really are.

Conditions Size Affected
Light rain (under 1/2 inch/hour) Tiny and below reduced to half speed.
Moderate rain (1/2 inch to 1 inch/hour) Small creatures reduced to half speed; Tiny and below can't fly.
Heavy rain (>1 inch/hour) Medium creatures reduced to half speed; Small and below can't fly.
Monsoon (>3 inches/hour) No creature besides those with innate flight ability can remain aloft; even those are reduced to half speed, except for air elementals.

Wounds and Flying

A creature with maneuverability of less than Perfect loses flying ability the more damage it takes, unless it has innate flight (like an elemental). For every 25% of its hit points it loses, a creature is reduced by one maneuverability class, to a minimum of Clumsy. This represents blood loss, pain, and damage to vital organs (wings and muscles) that hinders the ability to fly. A creature's fly speed is also reduced by 10 feet per 25% of its hit points it loses, to a minimum of 10 feet per round. Again, this does not apply to elementals or creatures with innate flight ability. A creature reduced to less than 25% of its hit points cannot take any actions besides keeping itself in the air, and even then it can move at only half speed and can't perform any aerial maneuvers; a creature reduced to 10% of its original hit point total cannot fly at all; if is in the air, it immediately starts to fall.

Even if the creature is immediately healed back up to a better hit point bracket (from 25% of hit points to 50%, e.g.), it must spend at least one full round at rest (on the ground, sitting in a tree, etc.), giving its body time to readjust and take the strain off the previously damaged muscles and body parts, before it can regain the higher maneuverability class.

Obviously, damage directly to the wings (for creatures that use wings) inhibits a creature's ability to fly much more effectively and quickly than damage to the creature as a whole. In this case, attacks against the wings that deal damage are considered to be twice as effective for purposes of determining a creature's ability to fly.

For example: A griffin with 48 hit points is hit in one wing by another rider's sword, taking 6 points of damage. Since all this damage was to the wing, it counts double – the griffin is treated as being reduced to 25% of its hit points (12 is 25% of 48), and suffers accordingly.

A creature can withstand up to 25% of its total hit points in damage to its wings before they are crippled sufficiently that the creature cannot use them to fly. If only one wing is crippled, it can spiral down to the ground, though it must make a DC 15 Reflex save to avoid crashing and taking 1d4 points of damage per size category above Tiny (1d4 for Small, 2d4 for Medium, etc.). If both wings are crippled, the creature cannot control its descent and falls straight to the ground; it cannot pull out of a fall in this case.

For example: If the griffin mentioned above took another 6 points of damage to the same wing, it would be crippled; it could spiral down to a safe resting place, but it couldn't take off again until the wing were healed and it had sufficient time to rest and recover.

Underwater Combat

Land-based creatures can have considerable difficulty when fighting in water. Water affects a creature's Armor Class, attack rolls, damage, and movement. In some cases a creature's opponents may get a bonus on attacks. The effects are summarized in Table 2. They apply whenever a character is swimming, walking in chest-deep water, or walking along the bottom.

Ranged Attacks Underwater

Thrown weapons are ineffective underwater, even when launched from land. Attacks with other ranged weapons take a -2 penalty on attack rolls for every 5 feet of water they pass through, in addition to the normal penalties for range.

Attacks from Land

Characters swimming, floating, or treading water on the surface, or wading in water at least chest deep, have 9/10ths cover (+8 bonus to AC, +4 bonus on Reflex saves) from opponents on land. Landbound opponents who have freedom of movement effects ignore this cover when making melee attacks against targets in the water (this does not apply to ranged attacks). A completely submerged creature has total cover against opponents on land unless those opponents have freedom of movement effects. Magical effects are unaffected except for those that require attack rolls (which are treated like any other effects) and fire effects.


Nonmagical fire (including alchemist's fire) does not burn underwater. Spells or spell-like effects with the fire descriptor are ineffective underwater unless the caster makes a Spellcraft check (DC 20 + spell level). If the check succeeds, the spell creates a bubble of steam instead of its usual fiery effect, but otherwise the spell works as described. A supernatural fire effect is ineffective underwater unless its description states otherwise. The surface of a body of water blocks line of effect for any fire spell. If the caster has made a Spellcraft check to make the fire spell usable underwater, the surface still blocks the spell's line of effect.

Table 2: Combat Adjustments Underwater

Condition Slashing or Bludgeoning Tail Movement Off Balance?1
Freedom of movement normal/normal normal/normal normal No
Has a swim speed -2/half normal normal No
Successful Swim check -2/half2 -2/half quarter or half3 No
Firm footing4 -2/half -2/half half No
None of the above -2/half -2/half normal Yes

1 Creatures flailing about in the water (usually because they failed their Swim checks) have a hard time fighting effectively. An off-balance creature loses its Dexterity bonus to Armor Class, and opponents gain a +2 bonus on attacks against it.

2 A creature without a freedom of movement effect or a swim speed makes grapple checks underwater at a -2 penalty, but deals damage normally when grappling.

3 A successful Swim check lets a creature move one-quarter its speed as a move action or one-half its speed as a full-round action.

4 Creatures have firm footing when walking along the bottom, braced against a ship's hull, or the like. A creature can only walk along the bottom if it wears or carries enough gear to weigh itself down — at least 16 pounds for Medium creatures, twice that for each size category larger than Medium, and half that for each size category smaller than Medium.

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