Aura

Version 0.30: This article may not be up to date for the latest stable release of Crawl.

Auras are passive abilities that emanate out of certain characters and monsters, affecting anything that comes within their range. The exact effect this has varies by aura.

Halo

Halo auras emanate forth from certain holy weapons, monsters, and characters. It has the following effects:

• Negates invisibility of anything inside.
• Makes everything inside easier to hit. Attackers gain 1 + 1d8 to-hit against anything inside. When players emit a halo, they aren't any easier to hit.
• Players have their stealth reduced by roughly x2.5.

Sources:

• Worshipers of the Shining One receive a halo with range based on piety (very small to nearly your entire line of sight)
• Characters wielding an orb of light or the unrand artifact morningstar Eos receive a medium halo.
• Most holy monsters have halos, the size of which depends on the monster in question. Weaker creatures like holy swine and sun moths have tiny halos while powerful creatures like seraphim and ophanim have extremely large halos.

Umbra

The opposite of a halo, umbras emanate forth from unholy angelic beings. It has the following effects:

• Reduces the accuracy of all within the aura. Demons, undead, and worshippers of Dithmenos and Yredelemnul are immune to this effect.
• When players emit an umbra, their stealth increases by a factor dependent on source. ×1.5 for the ring of Shadows, ×1.0 to ×2.0 (depending on piety) for Dithmenos worshippers.
• Allows use of Dithmenos' Shadow Step ability.
• Negates the effect of any halo they overlap with.

Sources:

• Profane servitors have a large umbra.
• Wearers of the ring of Shadows have a medium umbra.
• Worshipers of Dithmenos receive an umbra with range based on piety (very small to your entire line of sight)

Ring of Flames

The Ring of Flames emanates one tile all around their source, creating flame clouds. These clouds linger for a few turns even after the source moves away. It has the following effects:

• Negates any Ice Magic that strikes the clouds.
• Deals fire damage to anything standing in the clouds (but does not injure the source).

Sources:

• Players can wear the salamander hide armour to gain this aura.
• Asmodeus has a permanent Ring of Flames aura surrounding him.

Polar Vortex

The Polar Vortex aura emanates when you cast the spell of the same name. It has the following effects:

• Deals heavy, partially irresistible cold damage to everything (except the source) within the aura.
• Moves all affected targets (monsters, items, clouds, etc.) counterclockwise around the source each turn.

Sources:

• Players and monsters can cast the spell to temporarily gain this aura.
• Diamond obelisks and twisters have permanent Polar Vortex auras surrounding them.

Silence

When Silence auras emanate from a monster or the player, most creatures within the aura lose the ability to make any noise, including speech. This prevents:

• Reading scrolls
• Casting spells (all spells for the player)
• Using divine abilities
• Shouting

Monsters are unable to use spells/abilities with the "Wizard", "Divine", or "Vocal" spell slot flags. Monsters that use "Magical" or "Natural" abilities (including demons) are immune to silence.

When players emit the aura, their stealth is reduced by 50.

Sources:

• Players can cast the Silence spell or use a scroll of silence to temporarily gain this aura.

The following enemies cast Silence:

• & Ereshkigal
• A Mennas

The following enemies may be able to cast Silence, depending on their spell set:

• & Pandemonium lord (7.5% chance)

The following enemy inherently radiates Silence:

• W Silent spectre (as a permanent 12-tile aura, whether awake or dormant)

History

• In 0.27, Tornado was replaced with the cold themed, functionally similar Polar Vortex.
• In 0.26, the Ring of Flames spell and aura is now triggered by the salamander hide armour.
• Prior to 0.19, Powered by Death gave regeneration from nearby corpses, relying on an aura to do so.
• The Moth of suppression and Suppression auras were added in 0.12, and removed in 0.14.