Aethyr Chaos Surges

Concentrated Aethyr wants to flow back into the weave, and when the structure holding it slips, it floods out as a chaos surge. Aethyr Instability and Chaos Events describes why; this page gathers the rules. The more Aethyr is involved, the more dice the surge rolls, and the further and longer its effects reach.

Every surge should change the story. A surge can help or hurt, but it always shifts what happens next: what someone can do, what someone knows or wants, or the place itself.

The Chaos Surge Roller does the rolling for you.

When a Surge Check Happens

The GM calls for a surge check when one of these happens. The Surge Charge is how many d20s the check rolls.

Trigger	Surge Charge
Casting a spell of 1st level or higher in an Aethyrstorm or an Aethyr Rift, or anywhere the weave is unstable, overcharged or distorted (Odamancy)	The spell slot’s level
Using Somamantic magic (innate spellcasting, or Aethyrflame Features that need no components) in the same places	Half the magic’s level, rounded down
Failing an Anti-Magic Instability Check	The level of the magic you tried to nullify, plus the amount by which the check exceeded your unspent Nullification Points
Sourcecasting: consuming Source in the blood to fuel a spell	The spell slot’s level, plus extra dice the GM sets for the Source consumed (1 for each is a good start)
Agitating, igniting or striking material Aethyr (Lyrium, Source, Aethyrium)	A vial or single dose 1, a pouch or weapon charge 3, a crate or cell 6, a stockpile 9
Failing a spellcrafting, enchanting or alchemy check by 5 or more	The level of the spell, or the item or potion’s spell level
A rule that names a surge’s severity	No roll: use that severity

In a stable weave, ordinary casting never calls for a surge check; the other triggers still do. In an Aethyr Scarcity Zone, nothing surges.

The Weave Adds Dice

Where the Aethyr is concentrated, more of it breaks loose. Add these dice to every surge check, whatever triggered it:

Where	Extra dice
A stable weave (most places)	+0
An Aethyr Node	+1
An Aethyrstorm, or a weave that is overcharged or distorted	+2
An Aethyr Rift	+3

The GM can add another die for other concentrations of magic: a ritual circle, several casters working together, or the site of an earlier surge. In an Aethyr Rift, even a cantrip rolls 3 dice.

Rolling the Surge

Roll the Surge Charge in d20s. Each die that rolls under 10 adds 1 to the surge’s severity, up to 5. Extra dice beyond that are ignored.

Severity	Surge
0	No surge. The weave shivers: roll a surge sign.
1	Minor
2	Moderate
3	Severe
4	Critical
5	Catastrophic

Before rolling the result, the creatures involved can steer the surge. Then the GM rolls a d100 on the table for that severity in the Aethyr Chaos Surges compendium: 1–33 is a positive result, 34–66 a negative one and 67–100 a chaotic one. Every surge also shows a surge sign.

Example. A spellcaster casts a 5th-level spell during an Aethyrstorm. The Surge Charge is 5 for the spell slot plus 2 for the storm: 7d20. The dice come up 5, 7, 9, 13, 15, 16 and 18, three under 10, so the surge is Severe. Nobody steers it, and the GM rolls 42 on the Severe table: Aethyric Sickness.

Odds

How often each severity comes up for a pool of dice:

Dice	None	Minor	Moderate	Severe	Critical	Catastrophic
1	55%	45%	0%	0%	0%	0%
2	30%	50%	20%	0%	0%	0%
3	17%	41%	33%	9%	0%	0%
4	9%	30%	37%	20%	4%	0%
5	5%	21%	34%	28%	11%	2%
6	3%	14%	28%	30%	19%	7%
7	2%	9%	21%	29%	24%	15%
8	1%	5%	16%	26%	26%	26%
9	0%	3%	11%	21%	26%	38%

Spells of 3rd level or lower in a stable weave never go past Severe. High-level magic in an Aethyrstorm or a Rift is meant to be dangerous.

Steering the Surge

Practitioners spend years learning to calm the weave, and others learn to ride it. Once the severity is known, and before the d100 is rolled:

• Ground the Surge. A creature within 30 feet of the surge that has Nullification Points can use its reaction to spend points equal to the severity and lower it by 1. Grounding disperses Aethyr rather than unravelling a spell, so it doesn’t call for an Anti-Magic Instability Check. Several creatures can ground the same surge, each using its own reaction; grounding a Minor surge disperses it entirely.
• Embrace the Chaos. The creature that caused the surge can raise its severity by 1 (not past Catastrophic). If it does, the GM rolls the d100 twice and that creature picks the result.
• Steady the Weave. If the surge is Moderate or larger and wasn’t embraced, the creature that caused it can make a spellcasting ability check, DC 10 + twice the severity. On a success, the GM rolls the d100 twice and the caster picks the result. On a failure, the GM rolls twice and picks the one that twists the scene more.

A creature without a spellcasting ability uses Constitution for Steady the Weave.

Severity and Reach

Each severity reaches further and lasts longer than the one before, and changes something bigger in the story. Use this to judge results at the table and to write new ones.

Severity	Reach	Typical duration	What it changes
Minor	The source creature, or within 10 feet	1 minute to 1 hour	A moment: a quirk or a complication in this scene
Moderate	Creatures within 30 feet	10 minutes to 24 hours	The encounter: how this scene plays out
Severe	Everything within 60 to 100 feet	Strong for 1 minute to 1 hour, and may linger	The session: the plan has to change
Critical	Up to a mile; can permanently alter a creature or object	Hours to permanent	The arc: people hear of it, and a new problem, rival or ally appears
Catastrophic	A mile or more; can reshape a place	A day to permanent	The campaign: a new place on the map, a quest, or a power that takes notice

Critical and Catastrophic surges are noticed. Decide who comes looking: scholars of the Aethyr, a temple, rivals, the authorities, or creatures drawn to loose Aethyr. A surge that leaves a lasting mark on a place belongs on the campaign’s map and in its calendar.

Writing Surge Results

A good result changes at least one of these:

• What someone can do: a real change to the rules, good or bad.
• What someone knows or wants: something revealed, a new motive, a relationship, a reputation.
• The place: terrain, access, light, or who is now on their way.

Write the effect first, then the twist: what it does to the scene. Prefer complications to repeated damage. Permanent harm should come with a cure the party can go and find, and great boons with a price or with attention from something powerful.

Surge Signs

Every surge check shows a sign, even when nothing surges. Roll a d20:

d20	Name	Sign
1	Colored Light	Every light within 30 feet turns a single color for a moment.
2	Strange Flames	Nearby flames gutter and burn in a new color for a minute.
3	Humming Metal	Metal nearby hums, and blades and buckles ring faintly.
4	Lagging Shadows	Shadows trail a heartbeat behind the creatures that cast them.
5	Sudden Scent	The air smells of ozone, then of flowers, then of nothing.
6	Drifting Runes	Glowing runes drift through the air and fade.
7	Wild Growth	Flowers or mushrooms push up through the ground around the source.
8	Swirling Breeze	A gust swirls through, lifting loose papers, hair and cloaks.
9	Floating Trinkets	Small loose objects rise an inch and drop.
10	Distant Thunder	Thunder rolls once from a clear sky.
11	Whispers	Faint whispers sound nearby, too soft to make out.
12	Unseen Music	A few notes of music play from nowhere.
13	Static	Sparks crackle along fingertips, and hair stands on end.
14	Late Reflections	Reflections in nearby surfaces move a moment late.
15	Echo	Every sound nearby echoes once, a second late.
16	Motes of Light	Bubbles or motes of light stream from the source and fade.
17	Frost	Frost or dew beads on every surface within 10 feet.
18	Glimpse	A tiny portal blinks open on a strange sky, and shuts.
19	Glow	The source creature's eyes or hair glow faintly for a minute.
20	Whirlwind	Leaves, dust or ash spin in a small whirlwind and settle.