An aura surrounds a creature with an effect that acts on the squares around it during battle. The creature's description shows each aura with a value, for example Chill (6) or Fear (5). The value sets how often the aura acts and, for the strongest auras, how far it reaches.

Auras deliver their effect in one of two ways. A cloud aura fills nearby squares with clouds that stay there and act on anyone inside them. A direct aura strikes creatures near the carrier the moment it pulses. Protection depends on the effect rather than the delivery: most direct auras and the disease clouds of a Plague Carrier allow a Magic Resistance check, Fear and Dread attack morale instead, and the elemental clouds are resisted by the matching resistances.

Aura	Delivery	Effect	MR check	Magic path	Does not affect
Heat Aura	cloud	heat clouds, fatigue	none	-	-
Chill Aura	cloud	frost clouds, fatigue	none	-	-
Poison Cloud	cloud	poison clouds	none	-	-
Plague Carrier	cloud	disease clouds	Penetration 7	none	inanimate, the already diseased
Sleep Aura	direct	sleep	Penetration 11	Glamour	friendly, mindless, undead, inanimate
Nightmare Aura	direct	1 false damage	Penetration 11	Glamour	friendly, mindless
Mind Slime	direct	slowed for the battle	Penetration 15	Astral	mindless, Void Sanity
Disbelieve	direct	1 damage to illusions	Penetration 12	Astral	all but enemy illusions
Soul Vortex	direct	1 life drain	Penetration 11	Death	inanimate, the carrier and its mount
Plague	direct	plague infection	Penetration 12	none	inanimate (demons and spiritform resist via disease resistance)
Fear and Dread	direct	morale loss	none	-	friendly, morale 50 or more; Dread: True Sight, Spirit Sight, the blind

The Penetration figure is the check's base roll. The carrier adds half its magic level in the listed path to it. On the other side, a victim that is a commander in its own right resists with half of its own level in that path, rounded down; ordinary troops have no commander record and get nothing. A check with no path is fixed for both sides.

The strike auras of spells such as Dance of Ephemeral Swords and Shroud of Flying Shards are attacks with their own rules, and this page does not cover them.

An aura acts in pulses. The game checks each creature's auras every 320 ticks, 23.4 times per combat round, and each pulse strikes one square. The two delivery families roll for pulses differently.

Placement differs too. A direct aura with strength below 10 puts every pulse in the 3x3 block of squares centred on the carrier. From strength 10 up it uses the 5x5 block. The two block sizes are fixed: more strength buys more pulses, never more reach, until the 600 threshold below. Pulses always centre on the carrier, so an aura cannot creep across the battlefield. A cloud puff instead takes a short random walk from the carrier's square before it settles, so clouds can end up several squares away no matter the value.

A pulse that lands on an empty square does nothing, and a puff that walks off the battlefield is lost. The particle effects play either way, so an aura looks busier than it is.

An aura with a value above 600 abandons local placement entirely. It no longer rolls for pulses at all: every check it strikes a fixed number of squares, scattered at random over the whole battlefield, about fifty of them on a standard field. One creature reaches this behaviour: the Doom Horror Kurgi - Slave to Unreason, whose Mind Slime (665) washes over the entire battle.

All auras stop the moment the battle has a winner: the instant one side has nothing left on the field (or all units are fleeing), no aura fires again.

The "Twilight Falls" rule of very long battles is a separate mechanism. When Twilight falls at round 100 and dispels every temporary effect, spell-granted auras such as Soul Vortex vanish with it, and so do the Plague and Slowed conditions, while innate auras keep working. Item-granted auras survive it: the engine puts item abilities straight back after the wipe.

Four auras lay clouds, and the trait itself only ever lays level 1 clouds. A puff that lands on a square already holding that cloud type has a 5% chance to raise it to level 2, and that is the most an aura can build. Higher cloud levels exist, but only spells lay them. The clouds act on their occupants exactly twice per round and thin out on their own: a heat cloud loses about 1.8 levels per round in clear weather, 2.8 in rain and 3.8 in a storm, and frost or disease clouds thin at half those rates. All cloud damage ignores armour. The Clouds page lists what every cloud type does per level.

Clouds do not pick sides. They act on friend and foe alike, and the carrier stands in its own cloud.

The creature radiates heat, and its pulses lay heat clouds. A level 1 heat cloud deals 2 armour-negating heat fatigue damage per application, twice a round. Every application that gets through also rolls to set the victim on fire.

The burning roll is the damage left after resistance, out of 75. Take the cloud's heat damage, subtract Fire Resistance, and the victim burns if a d75 comes up under what is left. A level 1 cloud against an unprotected victim leaves 2, so the roll is 2 in 75. The damage has to land before the roll happens at all. In play that comes to 1.7% per application, 3.3% per round.

Fire Resistance counts double here, and it comes off the damage before the burning roll rather than after it. One point is enough to stop a level 1 cloud setting anyone alight, because doubled it cancels the cloud's 2 points exactly. Two points do the same for a level 2 cloud. Separately, and regardless of the cloud, a creature with 10 or more Fire Resistance can never burn. Neither can anything standing underwater.

The value moves with the surroundings: plus 1 per point of Heat scale in the province, minus 1 per point of Cold scale, and plus 1 per level of Fire magic for commanders. Rain does not change the value. It only makes every kind of cloud fade faster.

The plain heat aura switches off underwater. A second attribute, underwater heat, works everywhere, and the game shows the two as one summed Heat value. The Flame Jelly is the only creature with the underwater kind.

A heat puff that lands on a frost cloud removes one level of the frost instead of settling, and a frost puff does the same to heat, so the two clouds never share a square.

About thirty monsters have a heat aura, from Salamander (6) to Baphomet (15), median 6.

The creature radiates cold, and its pulses lay frost clouds. A level 1 frost cloud deals 2 armour-negating cold fatigue damage per application, twice a round. Every application that gets through also rolls to freeze the victim.

The freezing roll works exactly like the burning one above: the damage left after resistance, out of 75. Subtract Cold Resistance from the cloud's cold damage and the victim freezes if a d75 comes up under what is left. That is 2 in 75 for a level 1 cloud against an unprotected victim. Once the damage roll itself is counted it comes to 1.7% per application and 3.3% per round.

Cold Resistance counts double, and it comes off the damage before the freezing roll. One point is enough to stop a level 1 cloud freezing anyone, and two points do the same for a level 2 cloud. Separately, and regardless of the cloud, a creature with 10 or more Cold Resistance can never freeze.

The value mirrors Heat Aura: plus 1 per point of Cold scale, minus 1 per point of Heat scale, and plus 1 per level of Water magic for commanders. Snowfall during the battle adds a further 2. Chill works underwater.

About twenty monsters have a chill aura, from Winter Wolf (6) to Niefel Jarl (15), median 7. The Crown of the Frost King item grants Chill (25), a larger aura than any monster's own.

The creature trails poison clouds. The trait lays level 1 clouds only, and a level 1 poison cloud deals 1 armour-negating poison damage per application, with no Magic Resistance check. Stronger poison clouds come only from spells. Nothing modifies this aura: scales and weather leave it alone. It works underwater.

About forty monsters have it, from the Hydra (8) through the Tarrasque (10) to the Daughter of Typhon (12), median 8.

The creature trails clouds of disease. Anyone standing in one must pass a Magic Resistance check or become diseased. Against the low-level clouds an aura lays, the check comes at Penetration 7 instead of the usual 11. It belongs to no magic path, the carrier's own magic adds nothing to it, and disease resistance does not apply: the Magic Resistance roll is the only protection. Inanimate creatures are immune, Ethereal creatures escape 75% of the time, and a creature that is already diseased is never checked again.

Plague Carrier lays disease clouds and nothing else. The Plague aura further down this page is a separate, contagious effect.

About a dozen monsters have it, among them the Mummy (8), Lemuria's Apparition (5), and the Unfettered (14), the final form of the Eater of the Dead, whose cloud grows from 5 to 14 as it feeds.

Six direct auras force a Magic Resistance check on every creature their pulses strike, and a passed check negates the pulse completely. The roll works the same way as for spells: the aura rolls its Penetration plus DRN against the victim's Magic Resistance plus DRN, and the aura wins ties.

• The base Penetration is 11, or 15 for Mind Slime.
• Sleep Aura, Nightmare Aura, Mind Slime and Soul Vortex add half the carrier's magic level in their path, plus any penetration bonus from items. Only commanders have magic levels, so the same aura on an ordinary soldier gets no bonus at all.
• The victim adds half the level its commander has in the aura's path to its resistance.
• Disbelieve and Plague instead carry a fixed 1 point of penetration, so their rolls come at 12.

Fear and Dread are direct auras too, but no Magic Resistance check is involved. They have their own section below.

Nearby enemies must pass a Magic Resistance check or fall asleep. The check is a Glamour effect. Mindless, undead and inanimate creatures are immune, and the aura never touches friendly troops.

A sleeping unit's defence drops to zero, though attacks against it still roll. Any damage wakes the sleeper, except poison damage, so poison clouds let their victims sleep on while the poison works. The Undreaming ability grants extra Magic Resistance against this aura, and against no other aura.

Its carriers are the three unique Mandeha demons (15), which EA Lanka summons one at a time with Summon Mandeha, and the Shuten-doji (10).

Nearby enemies must pass a Magic Resistance check or suffer horrible visions that deal 1 point of false damage. The check is a Glamour effect, and mindless creatures are immune. Against an illusion the damage is real.

No monster and no spell has this aura. Its only source in the game is the item Crown of the Whispering Dead, which grants Nightmare Aura (24).

Minds near the creature are exposed to visions from beyond. A victim that fails its Magic Resistance check is Slowed for the rest of the battle: half movement, half as many strikes, and a penalty of 2 to attack and defence.

The check is an Astral effect, and this is the hardest aura to shake off: it comes at Penetration 15 where every other aura starts at 11. Mindless creatures and creatures with Void Sanity are immune. Nobody else is spared, so Mind Slime slows the carrier's own army as readily as the enemy. The carrier itself is a lawful target too, but every creature that has this aura also has Void Sanity, so in practice the carriers never slime themselves.

Seven monsters have it, from the Polypal Mother (5) through the Void Lurker (25) to Kurgi - Slave to Unreason (665).

The creature strips away illusions. An enemy illusion struck by a pulse takes 1 armour-negating damage unless it passes a Magic Resistance check, and a passed check negates the hit outright. Real creatures are untouched. The unit panel calls this Disbelieve Aura, and its tooltip calls it Reality Aura.

The check is Astral, and the aura fixes its penetration bonus at 1, so the roll starts at 12 regardless of caster's own magic. An illusion that is itself a commander subtracts half its own Astral level, rounded down: Astral 2 or 3 brings the roll to 11, Astral 4 or 5 to 10, Astral 9 to 8.

One monster has it: the Bodhisattva of Mercy (25).

The creature drains the life of everything nearby. A victim that fails its Magic Resistance check takes 1 point of armour-negating life drain damage. The carrier heals half the damage dealt, up to a ceiling of one and a half times its maximum hit points plus 10, and recovers twice the damage as fatigue. The check is a Death effect, and inanimate creatures are immune.

The aura spares the carrier and its mount, and nobody else. It drains the carrier's own troops as readily as the enemy.

It comes from the spell Soul Vortex and always has strength 8, which comes out at about eight pulses per round.

A creature that catches the plague radiates this aura. Anything nearby must pass a Magic Resistance check or catch the plague too, and begin radiating it in turn. An infected creature takes 1d2 damage and 1d4 fatigue damage every combat round until it dies.

The check belongs to no magic path, so no magic pushes it through resistance. Its strength is always 2, so it spreads through long contact rather than in bursts. Inanimate creatures are immune. Disease resistance protects everyone else in proportion, and demons and spiritform creatures have it at full strength, so the infection never takes on them. Friendly troops are not spared.

The plague comes from the spell Plague, and the blade Woundflame makes its bearer an infected carrier as well.

Fear and Dread pulses wear down the morale of nearby enemies. They never touch friendly troops, and no Magic Resistance check applies.

Each pulse lowers the victim's morale by a fifth of the aura value, rounded down. The penalty is temporary, and it caps at the aura value itself or at 10, whichever is less. A value below 5 does nothing at all, and the effect grows only at every fifth point: values 5 to 9 act alike, as do 10 to 14. The pulses also build pressure toward squad rout checks, described on the Fear page.

These auras pulse more often than their number suggests, because the game adds 6 to the value when rolling for pulses. Fear (5) therefore pulses on 46% of checks, and always uses the wide 5x5 placement.

Creatures with 50 or more maximum morale, mindless creatures among them, ignore Fear and Dread entirely.

Dread works like Fear with one exception: creatures with True Sight or Spirit Sight, and creatures that cannot see at all, ignore it. When a creature has both auras, Fear is used. Dread only takes over when the Fear value is below 5. Every Dread source in the unmodded game grants exactly 5, so the rule only shows itself with mods: a modded creature with Fear (5) and Dread (20) still projects its weaker Fear.

Fear values come only in steps. Every fear monster in the game has 5, 8, 10, 15 or 20, and two of every three sit at exactly 5. The Eater of Gods (20) sits at the top and the Dagon (5) at the bottom. No monster has Dread of its own: it comes from the bless and from the spell Nightmare Masks.

Most auras are innate traits. Blesses, spells and items grant the rest.

The bless table has four aura picks:

Bless	Requires	Grants
Heat Aura	5	Heat Aura (3) and 10 Fire Resistance
Chill Aura	5	Chill Aura (3) and 10 Cold Resistance
Dread	8, Magic scale 1	Dread (5)
Fear	9, 1	Fear (5)

Spells:

• Soul Vortex gives its caster the Soul Vortex aura.
• Plague leaves the Plague aura on its victims.
• Breath of Winter surrounds the caster with Chill (8) and 10 Cold Resistance, and the caster's Water magic raises the aura further like any chill aura.
• Nightmare Masks lays Dread (5) on one battlefield square, plus one more square per level of the caster's Glamour.

Items:

The aura commands are #heat, #cold, #uwheat, #poisoncloud, #diseasecloud, #fear, #dread, #mindslime, #sleepaura and #nightmareaura.

everything below comes from reading the game's code and still needs in-game verification.

A thirteenth aura hides in the engine with no name, no icon and no source, so let's call it the Heretic Aura: it deals 15 armour-piercing fatigue damage to sacred units only, with no Magic Resistance check, and its strength works like any direct aura's. No monster, item or spell carries it, and no mod command sets it directly.

A mod can still reach it, because the engine leaves unit effect numbers open to spells. A spell whose effect number lies in the 500 to 699 range plants the unit effect named by its damage field on whatever it hits, at a strength of the effect number minus 499 (500 range) or minus 599 (600 range). The Heretic Aura is unit effect 326, so a modded spell with effect 611 and damage 326 wraps its targets in it at strength 12. The modding manual does not document the mechanism, and the difference between the 500 and the 600 range, probably how long the effect lasts, is unknown.

• Clouds for what each cloud type does per level
• Fear for morale, pressure and rout mechanics
• Magic Resistance for the resistance roll and penetration
• Unit Abilities for the full trait tables