Version 0.10 · not yet playtested
Eldritch magic is knowledge no mind was built to hold. Its power is real, but the reading of the sign, the speaking of the word, the glimpse past the veil, spends something that does not come back by morning: sanity. Where the arcane sorcerer refills a pool each night (see Arcane Sorcery), the eldritch scholar burns down a mind that heals only slowly, and pays for the deepest workings with a lasting derangement. This is the personal, mostly-permanent end of the family (see Alternative Magic Systems for the framework).
This supplement swaps the core’s stress fuel for a sanity track and its falter for a derangement. Everything else, the 3d6 ladder, the four magnitudes, magical harm, durations, the dry-caster poke, stands unchanged. If a rule is not below, it works as the core book says.
An eldritch caster has a sanity track of 4 + Wits points, drawn on the sheet. Wits is the casting attribute; forbidden lore is understood, not felt. Spend sanity to cast.
| Magnitude | Sanity | What it does |
|---|---|---|
| Cantrip | 0 | A small wrongness, at will. Never spends sanity. |
| Spell | 1 | One real effect now: a psychic bolt, a fear, a grasping horror, a glimpse. |
| Greater spell | 2 | An area of dread, a summoned horror, a fold in space. |
| Ritual | 0 | Slow communion, out of a fight. Costs time, not sanity (but see below). |
On a partial (9–12) take the reduced effect free, or spend +1 sanity for the full result. The buy is always optional.
Sanity does not refill on a rest the way mana does. A full night’s rest restores only 2 sanity. The mind mends slowly, and only quiet time far from the mysteries, a stretch of proper downtime, restores it completely. Plan a delve knowing the well trickles, not floods; a scholar who spends freely on the first day fights the last on a frayed mind.
You can always cast, the knowledge is there whether your mind can bear it or not. When you must spend sanity you do not have, cast anyway: the spell resolves, your sanity is stuck at 0, and you take a derangement, a lasting madness rolled below or chosen by the GM.
| d6 | Derangement |
|---|---|
| 1 | Phobia. A specific thing (the dark, deep water, crowds, fire) unmans you: −2 on any roll in its presence until you can flee it. |
| 2 | Paranoia. You trust no one. −2 to act on an ally’s plan or accept their help until the scene turns. |
| 3 | Compulsion. A ritual you must perform (count, cleanse, recite) before you act, or freeze for a round. |
| 4 | Hallucination. You see and hear what is not there. The GM may lie to you about a scene once per session. |
| 5 | Obsession. A fixation (a symbol, a truth, a person) pulls your attention; −2 to disengage from pursuing it. |
| 6 | Fugue. Under stress you may lock up: on a miss in a hard moment, lose your next action to a staring spell. |
Derangements are permanent until treated, by long care, a quest, or a cure rarely found. They stack. A veteran of the eldritch arts is a broken thing held together by will, and that ruin is the story the source tells.
Every eldritch bundle grants Whisper of Unreason, the at-will poke for a spent mind. One action, a maddening murmur at one target for 2 magical harm (ignoring armor), or leaving it briefly Frightened, one or the other, rolled to hit. It never rivals a real weapon or the bolt. Reflavor it, a wrong syllable, a half-glimpsed shape, but hold the cap.
Setting flavors:
A ready-to-use eldritch catalog, sorted by magnitude. Copy chosen entries onto a spell-book sheet. Damage numbers are the L1 default; a playbook’s damage step scales them. All damage is magical harm.