Eldritch Madness
Eldritch Madness (abbr. EM) is a condition that accumulates in levels, representing the progressive deterioration of a creature's mind through exposure to eldritch forces. It functions similarly to exhaustion — each level adds new penalties and abilities — but where exhaustion reflects physical wear, Eldritch Madness reflects the mind's slow unravelling under the weight of things it was never meant to perceive.
Eldritch Madness can be inflicted by proximity to aberrations, eldritch auras, certain dark artefacts, and other sources of void energy. It is not merely a debuff — at higher levels it begins to grant strange and unstable abilities, as the afflicted mind starts to resonate with the forces that are breaking it.
Levels of Eldritch Madness
Level 1 — Whispers of the Void
The first cracks appear. The afflicted creature suffers disadvantage on Wisdom saving throws and Wisdom (Perception) checks. In exchange, they gain the ability to speak and understand Deep Speech.
Level 2 — Unnatural Insight
The mind begins reaching beyond its limits. The creature gains advantage on all Intelligence (Arcana) checks, but suffers disadvantage on all Charisma and Wisdom checks.
Level 3 — Fractured Reality
The veil between the material world and what lies beyond it thins. The creature can see into the Ethereal Plane up to 30 feet, but also begins to suffer from illusions and hallucinations whose content and timing are unpredictable.
Level 4 — Chaotic Surge
Magical energy becomes volatile and unstable. When the creature casts a spell, they roll a d6. On a 6, the spell is treated as one level higher — but the caster also takes psychic damage equal to the spell's level.
Level 5 — Eldritch Resonance
The creature's body begins to phase in and out of reality. They gain resistance to non-magical damage, but become vulnerable to psychic and radiant damage.
Critical Madness Events (Level 5 Sub-Levels)
A creature at Level 5 Eldritch Madness cannot gain a sixth level directly. Instead, whenever an effect would increase their Eldritch Madness further, they suffer a Critical Madness Event — an acute episode of eldritch instability. Once a creature accumulates 3 Critical Madness Events, their Eldritch Madness increases to Level 6.
Critical Madness Event counters reset at the end of a long rest.
Level 6 — Mind-Shattered
The mind collapses entirely. The creature becomes an NPC under the DM's control, driven to madness and potentially transformed into an eldritch abomination. As the mind shatters, it erupts — casting a random Eldritch Arcanum spell centred on the creature itself.
Active Abilities
Each level of Eldritch Madness unlocks a power that can be applied to spells. These abilities are cumulative — a creature with Level 3 EM has access to the abilities from Levels 1, 2, and 3. Using these abilities always carries the risk of accelerating further deterioration.
| Level | Ability | Effect | Risk |
|---|---|---|---|
| 1 | Eldritch Empowerment | When casting a damage spell, add an extra damage die. | Roll a d6. On a 6, gain one level of Eldritch Madness. |
| 2 | Abyssal Echo | When casting a spell with a duration, double that duration. | Roll a d6. On a 3 or 6, gain one level of Eldritch Madness. |
| 3 | Void's Grasp | When casting a spell requiring a saving throw, impose disadvantage on the target's first save. | Roll a d6. On a 1, 3, or 6, gain one level of Eldritch Madness. |
| 4 | Eldritch Resonance | When casting an area spell, increase the affected area by 50%. | Roll a d6. On a 1, 3, or 6, gain one level of Eldritch Madness. |
| 5 | Cosmic Reversal | When casting a spell that restores hit points, deal that amount as Vortex damage to a creature within range instead. | Roll a d6. On a 1, 3, or 6, gain one level of Eldritch Madness. |
Recovery
Removing Eldritch Madness is difficult and rarely straightforward. Known methods include:
- Isolation and Meditation — Three days of solitude, meditating 8 hours per day. At the end, make a Wisdom saving throw (DC 15 + current EM levels). On a success, remove one level of Eldritch Madness. On a failure, gain one level of Exhaustion instead.
- Sanctified Ground — Spending a week in a genuinely holy location may allow a Wisdom saving throw to remove a level, at the DM's discretion.
- Magical Intervention — Certain spells and rare artefacts can remove levels of Eldritch Madness directly.
- Other Means — Quests for rare cures, forbidden knowledge, or bargains with unknown entities have been rumoured to offer relief — each with their own considerable costs.