07 Spell Creation Guide

Purpose: This guide is for both DMs and players who want to create new spells (Powers) that feel mechanically balanced and tonally consistent with the world of Ersetu. Read this after 06 The Magic System — that chapter covers how casting works; this one covers how to design what gets cast.

Magic in this world is applied physics, not wish-fulfilment. Every spell should feel like a precise, engineered application of mana through a matrix of mana canals. When designing a spell, ask yourself:

1. What is the mana physically doing within the canals? Is it compressing air, restructuring molecular bonds, warping spatial coordinates, or stimulating neural pathways? If you can't describe the physical transformation, the spell is too vague.
2. What are the limits? Every spell has a cost, a range, a duration, and a failure mode. A spell with no limitations is not a spell — it's a plot device.
3. What school does this belong to? If you can't place it cleanly in one school (or a school + specialization), you're probably blending effects that should be two separate spells.
4. Does this feel like something a student would learn at this tier? A Tier 1 effect should be something a first-year could manage with concentration; a Tier 5 effect should terrify a senior professor.

2. Anatomy of a Spell

Every spell in this vault follows a consistent structure. When creating a new spell, replicate this format exactly:

YAML Frontmatter

---
tags: [spell, school-name]
type: spell
tier: 1-5
magic_school: SchoolName
specialization: None or SpecName
cost: (equal to Tier, unless modified)
description: "A brief one-line summary for the database index."
---

Body Format

### Spell Name
*School (Tier X)*
**Mana Cost:** X

Flavour description: What does this look like? What canal structure does the caster shape? What does the target experience? Write 2-4 sentences of evocative, grounded prose.

**System:** The mechanical resolution. Include:
- What attribute + skill is rolled (how the canals are shaped)
- The difficulty (Target Number)
- What happens on success (damage, duration, effect)
- Any specific Overcharge scaling points (or just general guidelines)
- Any special failure consequences (errors in the canal geometry)

3. The Tier Power Budget

This is the most important section for balance. Each tier has a strict power budget. A spell must fit within its tier's ceiling. If it exceeds any column, it belongs at a higher tier.

mana cost

Power Scaling by Tier

Use this table to calibrate the narrative weight of each tier — what the spell feels like in the fiction, who can cast it, and what kind of story moment it represents.

4. School Design Lenses

Each school has a distinct verb — the fundamental action its mana performs. When designing a spell, your effect must flow from that verb. If you find yourself stretching to justify why a spell belongs in a school, it probably doesn't.

5. Cross-School Spells

Sometimes a desired effect inherently spans the domains of multiple schools. When designing a cross-school spell:

1. Identify the primary school. This determines which Shaping skill is rolled. The spell is "purchased" using dots from this school.
2. Identify the secondary prerequisite. The collateral school (or schools) required. List this explicitly in the spell description.
3. The tier cannot exceed either school. If a spell is Tier 3 under its primary school and requires a secondary, the caster needs at least 3 dots in the primary and the listed dots in the secondary.

Example structure:

Homing Missile — Animation Class Tier 3
Cross-School Prerequisite: Projection Class 2
This means the caster needs Animation 3 and Projection 2 to learn this spell.

6. Worked Examples

See Spells Index for spell that are ready to go

Example A: Creating a Tier 1 Projection Spell

Step 1 — Intent: "I want a spell that lets me create a small burst of light to blind someone temporarily."

Step 2 — School Check: This is generating energy (light) from mana → Projection. ✅

Step 3 — Tier Budget Check:

• Damage: None (utility effect) ✅
• Range: 5m ✅
• Duration: Instant (1 round of blindness) ✅
• Targets: 1 ✅
• Complexity: One simple effect ✅
  → Fits cleanly in Tier 1.

Step 4 — Write it up:

### Flash Burst
*Projection (Tier 1)*
**Mana Cost:** 1

The mage channels a sharp pulse of mana into visible light,
releasing it as a blinding flash from their palm.

**System:** Roll Willpower + Projection vs the target's
passive Mind Defense. On success, the target is Blinded
for 1 round (they suffer -3 dice to all actions requiring
sight). No damage is dealt.

Example B: Creating a Tier 4 Alteration Spell

Step 1 — Intent: "I want a spell that turns a stone wall into liquid for 10 seconds so I can walk through it."

Step 2 — School Check: Restructuring existing matter → Alteration. ✅

Step 3 — Tier Budget Check:

• Range: Touch ✅ (but affecting a large structure)
• Duration: ~10 seconds (short but with major effect) — pushing Scene-level impact
• Area: A 2m x 2m section of wall — Large room-scale manipulation
• Complexity: Single effect but on a massive structural scale
  → This is restructuring dense inorganic matter on a significant scale. Tier 4.

Step 4 — Write it up:

### Liquidation
*Alteration (Tier 4)*
**Mana Cost:** 4

The mage presses their hand against a solid surface and
floods it with mana, temporarily dissolving the molecular
bonds holding the material together. The stone, metal, or
wood becomes a thick, viscous liquid for a brief window.

**System:** Roll Calculation + Alteration vs difficulty 7.
On success, a 2m x 2m section of non-magical wall becomes
passable liquid for a number of rounds equal to the
caster's Finesse. Anyone can walk through during this
window. The material resolidifies violently when the
duration ends — anyone still inside takes 4 Physical
Damage (Aggravated).

Example C: Creating a Tier 3 Cross-School Spell

Step 1 — Intent: "I want a ward that, when triggered, fires a concussive blast at the intruder."

Step 2 — School Check: The persistence and trigger are Abjuration (specifically the Ward specialization). The blast is Projection Class. The primary action is the ward (it sits there waiting), so this is an Abjuration spell with a Projection prerequisite.

Step 3 — Tier Budget Check:

• Range: Area-bound (10m radius ward zone) — Large room ✅
• Duration: Weeks (with crystal battery) — persistent ✅
• Damage: 2 Physical on trigger — moderate ✅
• Complexity: Combined effect — conditional trigger + energy release ✅
  → Persistent area + conditional trigger + secondary school damage = Tier 3.

Step 4 — Write it up:

### Concussive Trap Ward
*Abjuration (Tier 3)*
**Specialization:** Ward
**Cross-School Prerequisite:** Projection 2
**Mana Cost:** 3 (+ crystal battery for persistence)

The mage inscribes a geometric ward matrix around a
doorway or chokepoint, embedding a compressed Projection
charge into the ward's trigger layer. When an unauthorized
person crosses the boundary, the ward detonates the stored
energy as a focused concussive blast.

**System:** Ward creation requires a full scene of
uninterrupted preparation. Roll
Calculation + Abjuration vs difficulty 6 to set the ward.
When triggered, the intruder must resist with Athletics
vs difficulty 6. On failure: 2 Physical Damage and the
target is knocked prone. Each Overcharge point spent on the
original ward roll adds +1 to the trigger's difficulty.
The ward recharges after 1 hour if its power source
remains intact.

Example D: Designing a Spell Formula Item (Optional Support System)

Step 1 — Intent: "I want to create a ring that holds a Tier 2 ward so it can activate instantly in combat."

Step 2 — School Check: The player uses the Spell Formula support skill to anchor a chosen spell into an item. The underlying spell (the Ward) must be a spell the creator (or a collaborator) knows how to cast natively.

Step 3 — Tier Budget & Item Limits:

• The item must be resilient enough to act as an anchor (a solid metal ring works).
• The creator must have at least 2 dots in Spell Formula to safely store a Tier 2 spell into an item without the diagram collapsing.
• The resulting item activates instantly without a casting roll, but costs double the usual mana (4 mana instead of 2).

Step 4 — Write it up:

### Defender's Ring (Spell Formula Item)
*Spell Formula (Tier 2)*
**Item Required:** A sturdy metal ring (Affluent Funds).
**Stored Spell:** Tier 2 Abjuration (Ward specialization) (requires a collaborator or creator with Abjuration 2).

An intricately engraved ring that houses a compressed 
force-shield boundary, designed to trigger the moment 
the wearer is struck with significant kinetic energy.

**System:** Creating the formula takes a day of work and 
a successful Finesse + Academics roll. Once finished, 
the wearer can trigger the Ward as a free action in combat 
by feeding it 4 Mana. 

7. Common Pitfalls

8. GM Adjudication Tips

When a player proposes a homebrew spell during play:

1. Identify the school immediately. Ask: "What is the mana doing?" If they can't answer cleanly, the spell needs more thought.
2. Check the Tier Power Budget. Compare their proposed effect against the table. If it exceeds two columns, bump the tier.
3. Assign a difficulty on the fly. Use the tier's TN range as your baseline and adjust ±1 based on circumstances.
4. Ask for the cost. The mana cost is always equal to the Tier at minimum. If the effect is stretching the tier, charge +1 mana.
5. Define the failure case. What happens if they miss? At minimum: mana lost, spell fizzles. For Tier 3+: consider Mana Burn consequences or environmental backlash.
6. Reward creativity, punish vagueness. A player who describes exactly how their mana canals interact with the environment gets the benefit of the doubt. A player who says "I cast a thing" does not.

9. Quick Reference: Spell Template

Copy this template when creating a new spell file:

---
tags: [spell, SCHOOL]
type: spell
tier: X
magic_school: SCHOOL
specialization: None
cost: X
description: "Brief one-line summary."
---
### SPELL NAME
*School (Tier X)*
**Mana Cost:** X

Flavour description (2-4 sentences).

**System:** Roll [Attribute] + [School] vs difficulty X.
On success: [effect]. Overcharge: [scaling/options].
On failure: mana is lost; [additional consequences if any].