Fighting in Unusual Conditions (POCT)

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Since adventures are notoriously unpredictable, a surprising number of battles take place in the most inconvenient places. Player characters tend to get into fights while hanging on the side of a cliff, swimming in subterranean lakes, or while venturing into fantastic planes of existence. Last but not least, many magical spells can create strange effects. This next section addresses the most common of these unusual conditions.
==Limited Visibility==
Fighting at night or in dark settings is difficult—especially if your foe can see better than you can. As noted in the DMG, characters fighting in darkness or heavy fog suffer penalties to their attack rolls, damage bonuses, and Armor Classes.
===Moonlight or Moderate Fog or Rain===
Characters suffer a –1 penalty to attack rolls and saving throws. Since nothing can be seen more than 100 yards (60 squares) away, spell and missile ranges are limited; no missile scale combat can take place in an encounter.
===Starlight or Dense Fog or Heavy Rain===
Characters suffer a –3 to attack rolls and saving throws, a –2 penalty to AC, and only get 1/2 their normal damage bonus for exceptional Strength. Nothing can be seen more than 50 yards away (10 yards for dense fog or cloudy moonless nights), so spell and missile ranges are very limited.
===Total Darkness===
Characters suffer a –4 penalty to attacks, saves, and AC and receive no damage bonus for exceptional strength. No special attacks such as disarms, backstabs, or traps are allowed—the character can't see his own weapon, let alone his target.
==Water==
Underwater combat is described in some detail in the DMG. Here's a quick reminder of some of the difficulties of underwater combat.
===Weapon Restrictions===
Only type P weapons can be used effectively underwater; the water offers too much resistance to use any other kind of weapon except nets.
===Vision===
Under the best of circumstances, characters can see no more than 100 feet underwater (50 feet in fresh water.) For each 10 feet they descend, this range of vision is reduced by 10 feet; if a character is 30 feet underneath the surface of a lake, he can only see 20 feet. If it is dark outside or the water is muddy, this could be reduced even more.
===Movement===
Characters moving about underwater have to swim. See Swimming under Chapter 14: Time and Movement in the Player's Handbook.
Characters who are only wading are much less affected. Wading in knee-deep water reduces movement by 1/3. Wading in waist-deep water reduces movement by 1/2 and adds a one-phase initiative penalty to any action the character takes. Wading in shoulder-deep water reduces movement by 2/3, adds a two-phase penalty, and causes the character to lose any Dexterity adjustment to his Armor Class (although it does provide cover against someone firing missiles at the character).
===Fighting Underwater Monsters From the Surface===
It's always great fun when a wading character gets attacked by some aquatic horror. When a character fights against something that uses water for cover, slashing and bludgeoning weapons are useless. Only type P weapons can be used to attack underwater creatures, and there is a –2 penalty to hit. The wading character also loses any Dexterity adjustment to AC when attacked from beneath the surface.
==Climbing==
Cliffs and mountaintops are another awkward place for a fight. Adventurers seem to be drawn to the worst locations imaginable for their heroic battles and often find themselves under attack while they're clinging to a vertical wall of rock.
===Movement===
Climbing characters normally move 1 foot per round for each point of normal movement. A dwarf with an adjusted movement rate of 5 can climb 5 feet per round in good conditions. Refer to Climbing under Chapter 14: Time and Movement in the Player's Handbook.
===Fighting===
Climbing characters lose all AC bonuses for Dexterity and shield, and may have rear attack modifiers applied against them. They have a –2 penalty to attack, damage, and saving throw rolls. If a character is above his enemy, he gains a +2 bonus on his attack rolls; if he is beneath his enemy, he suffers an additional –2 penalty.
Any time a character is struck while climbing, she must make a climbing check, detailed in Chapter 14: Time and Movement in the PHB. Note: you can use a default check of 30% in good conditions.
===Fighting Flying Creatures===
Encountering angry giant eagles while clinging to a cliff is usually no fun at all. Unless they can hover, flying monsters can only make one pass every other round to attack climbing characters. If the PCs are facing the cliff (most climbers have to), the flying creatures get the benefit of rear attacks. Intelligent flyers may try to use their talons to drag a climber off the cliff; treat this as a grab attack. This forces a climbing check, and even if the character succeeds, he still must win the Strength contest to stay on the cliff side.
==Aerial Combat==
Aerial combat is described at length in Chapter 9: Combat under the optional rule Aerial Combat in the Dungeon Master Guide. Here's the gist of how these rules work in the Player's Option combat system.
===Initiative===
The more maneuverable flyer gains a –1 bonus to its initiative roll for each level of difference in Maneuverability Class between itself and its opponent. Creatures at home in the air have an easier time fighting while airborne.
===Threatening===
No aerial combatant threatens any adjacent creatures. Combat in the air just doesn't work that way; battles tend to take the form of joust-like passes at each other.
===Movement===
All fliers with a MC of B or worse must declare a half-move action every round just to stay in the air. Class B fliers can hover in position, but fliers with a MC of C or worse must move forward in this half-move to stay aloft. This requirement to keep moving means that a class C flier can make an attack against a stationary target once per two rounds, a class D flier once per three rounds, and a class E flier once per six rounds.
Gaining a point of altitude costs an additional movement point; a flier with a move of 18 could move 9 squares forward and 9 squares up with a full-move action. Diving allows the flier to add one point of free movement for each point of altitude it drops, so the flier with the 18 movement could move 36 squares in a full-move dive. Of course, it also has to drop 18 points of altitude (90 feet) to do this.
===Attacks from Below===
Creatures attacking from beneath an opponent cannot charge, but they may be in a blind spot. The defender can reply with an attack only if it has natural weapons or its rider is equipped with a size L weapon, such as a lance.
===Attacks from Above===
Creatures attacking from above may declare a charge by diving at their victims. Lances, spears, and a flier's natural talons or claws inflict double damage in a dive attack. In addition, the defender may not be able to reply to the attack if its only natural weapons are talons or hooves.
===Unseating a Rider===
Characters riding a flying mount can be “unhorsed,” just like characters on the ground. If the character is strapped into his saddle (a wise precaution), he is simply knocked off-balance in his seat and suffers the same penalties as if he had actually been knocked down on the ground—he is easier to hit and has to spend an action getting back in his seat.
Naturally, if a character is not strapped in, he risks the damage of a fall if he is unseated by any means.
==Combat on Other Planes==
Almost any conditions imaginable may be encountered in the various planes of existence. The Planescape™ campaign setting describes the general conditions of the various Outer and Inner Planes, but fights are also likely to occur in two other settings: the Astral and the Ethereal Planes.
===Astral Combat===
On the Astral Plane, a creature's tactical movement is based on its Intelligence score. Its move becomes 30 feet (6 squares) per point of Intelligence. In addition, Intelligence replaces Stength for purposes of determining attack and damage adjustments, and Wisdom replaces Dexterity for AC adjustments and missile fire. All missile ranges are doubled, but non-native characters suffer a –2 penalty to hit with missile attacks.
There are very few obstructions in the Astral Plane, and the encounter range is normally twice the longest missile range. Since this is most likely a great distance, astral combat should be run in missile scale. Fighting in the Astral is like aerial combat; creatures do not threaten each other, and can move in three dimensions.
If a character's astral self is killed, she immediately returns to her physical body with only 1 hit point. If the character is killed while physically on the plane, she is dead.
===Ethereal Combat===
Ethereal creatures move at their normal unencumbered rate, regardless of their equipment and armor. Unlike the Astral Plane, the Ethereal is a swirling mass of misty proto-matter that obscures vision; the Encounter Range is 10–40 squares (50–200 feet). Missiles tend to be slowed by the misty matter, and shots of medium range or longer just stop and hang in the air.
If a character is in the Border Ethereal, she can still perceive the shadowy outlines of the plane she just left. She can move through any objects or creatures without impediment. Of course, she is unable to affect things on the plane she is viewing, but she can only be affected by the magical gazes of a very limited number of monsters.