Magic System Interactions

How the four magic systems interact, oppose, and complement each other according to the Circle of Interaction.

The Circle of Interaction

The Circle of Interaction—also called the Circles of Interaction—describes how magical powers interact when exposed to each other. This fundamental diagram connects each of the four magic systems to the others, with the position of connecting lines delineating the nature of their interactions.

Diagram Layout

The Circle of Interaction arranges the four magic systems in a circular formation:

If the image is not available, see the text description below.

Visual Description: Four small circles positioned at the cardinal points: - Top (North): Divine magic, symbolized by an ankh - Right (East): Fae magic, symbolized by a tree or leaf - Bottom (South): Infernal magic, symbolized by a wreath - Left (West): Arcane magic, symbolized by an eye

The circle contains three types of connecting lines: 1. Horizontal and vertical lines through the center connecting opposites 2. Clockwise arrowed lines around the exterior indicating interference 3. Counter-clockwise arrowed lines indicating enhancement

The arrangement shows: - Opposite Actions: Divine ↔ Infernal (horizontal), Arcane ↔ Fae (vertical) - Circle of Interference (clockwise): Divine → Fae → Infernal → Arcane → Divine - Circle of Enhancement (counter-clockwise): Divine → Arcane → Infernal → Fae → Divine

Three Types of Interactions

The four magic systems have three distinct types of relationships:

1. Opposite Actions (Direct Opposition)

Two pairs of magic systems are in direct, violent opposition to each other:

Divine ↔ Infernal (Horizontal Opposition)

These systems are diametrically opposed in the most brutal fashion. When divine and infernal magic clash, they attempt to snuff each other out violently.

Core Mechanics: - Energy-Based Contests: Victory is determined by quantity of raw energy (spell level/mana cost), not skill, intelligence, or spell save DC - Higher Energy Wins: When opposite spells clash directly, compare the spell's level/mana cost: - Divine vs Infernal: Compare mana costs (spell level = mana cost for both) - Higher cost automatically triumphs - Tied Energy: If both spells use the same level/mana cost, both spells fail catastrophically. Both casters take force damage equal to the spell level used (minimum 1) - Close Contests: If the spell levels/mana costs differ by only 1, roll a d20 after the victor's spell resolves: - On a roll of 1-5: The victorious spell becomes ragged, unstable, and fizzles out uselessly despite winning - On a roll of 6-20: The spell works normally - Brutal Nature: These contests tend to be particularly brutal—victory means bludgeoning your opponent with as much overkill as you can muster

Game Mechanics: - Dispel Magic: Advantage on ability checks when dispelling opposite system spells - Counterspell: Advantage on ability checks when countering opposite system spells. If your counterspell uses mana/spell level 2+ levels higher than the target spell, it automatically succeeds - Area Effects: - Areas of strong divine presence (temples, holy sites, sanctified ground): Infernal magic cast in these areas has Disadvantage on spell attack rolls and spell save DCs are reduced by 2 - Areas of infernal corruption (demon-summoning sites, hell portals, corrupted areas): Divine magic cast in these areas has Disadvantage on spell attack rolls and spell save DCs are reduced by 2 - Saving Throws: Creatures have Advantage on saving throws against spells from the opposite system - Visual Effects: Clashes between opposite systems are flashy and spectacular, often dangerous to nearby creatures - Divine Burns: When divine casters exceed their limits and suffer burns, these cannot be healed through divine magic. Only Fae magic or natural recovery can heal divine burns.

Arcane ↔ Fae (Vertical Opposition)

These systems share the same brutal opposition relationship as Divine/Infernal, explaining why fairies are becoming rarer in areas with widespread arcane enchantment.

Core Mechanics: - Same mechanics as Divine ↔ Infernal, but comparing different resource types - Energy-Based Contests: Spell level/mana cost determines victor - Arcane: Uses mana cost (equal to spell level) - Fae: Uses spell slot level (traditional D&D spell slots) - Compare mana cost to spell slot level—they're equivalent (3 mana = 3rd level slot) - Mutual Destruction: Equal spell levels/mana costs cause both spells to fail - Ragged Victory: Close contests (within 1 level) may result in unstable spells

Game Mechanics: - Energy Comparison: Higher level/mana cost automatically wins direct clashes - Area Saturation: - Arcane-enchanted areas (wizard towers, magical laboratories, enchanted cities): Fae magic has Disadvantage on spell attack rolls and spell save DCs are reduced by 2 - Fae-saturated areas (deep wilderness, fey groves, ancient forests): Arcane magic has Disadvantage on spell attack rolls and spell save DCs are reduced by 2 - Creature Reactions: - Fey creatures are uncomfortable and may be harmed by strong arcane magic - Fairies avoid arcane-enchanted locations - Modern era: Widespread arcane enchantment in Imperial territory makes fairies rarer sightings - Dispel Magic & Counterspell: Same Advantage rules as Divine/Infernal opposition

2. Circle of Interference (Clockwise - One-Way Disruption)

The Circle of Interference—sometimes called the Circle of Annihilation—shows which power interferes with which. These interactions are much gentler than opposite actions but still significant.

Direction of Interference (clockwise): - Divine → Fae: Divine magic disrupts fae magic - Fae → Infernal: Fae magic disrupts infernal magic - Infernal → Arcane: Infernal magic disrupts arcane magic - Arcane → Divine: Arcane magic disrupts divine magic

Core Mechanics: - Gentler Than Opposition: These are not contests—the interfering energy simply causes the target magic to become unstable and fizzle out - No Energy Contest: Unlike opposite actions, interference doesn't involve comparing spell slot levels - Subtle Effects: More subtle and less spectacular than opposite action clashes - Prevents Casting: Interference affects spells being cast, not already active effects or shields - One-Way: The relationship is directional—if Divine disrupts Fae, Fae does not disrupt Divine

Game Mechanics:

Interference During Spellcasting: - When a creature attempts to cast a spell in the presence of interfering magic, the interfering caster (or the area itself) can use a reaction to force a concentration check - Concentration Check DC: 10 + the level of the interfering spell or effect (minimum DC 10) - For mana-based systems: Use spell level (mana cost equals spell level) - For Fae: Use spell slot level - On Failure: The target spell fails and the resource is expended (mana points, spell slot, or divine/infernal power) - On Success: The spell casts normally - Timing: This interference can only affect spells being cast, not shields, buffs, or other ongoing effects

Dispel Magic with Interference: - Advantage on ability checks when dispelling spells from a system you interfere with - The interference relationship doesn't affect spells from your own system (normal check) - The interference relationship doesn't affect spells that interfere with you (normal check)

Area-Based Interference: - Areas saturated with interfering magic can disrupt spells as they're being cast - GM determines DC based on area's magic saturation level - Creatures may need to make concentration checks to cast in these areas

Specific Examples: - A divine caster can disrupt a fae druid's spell as it's being cast (Divine → Fae) - Fae magic in an area can break an infernal warlock's concentration (Fae → Infernal) - Infernal magic can cause arcane spells to fizzle during casting (Infernal → Arcane) - An arcane wizard can interrupt divine spellcasting with interference (Arcane → Divine)

3. Circle of Enhancement (Counter-clockwise - Mutual Reinforcement)

The Circle of Enhancement shows which powers reinforce each other. These relationships are mutually beneficial and can create spectacular effects.

Direction of Enhancement (counter-clockwise): - Divine → Arcane: Divine magic reinforces arcane magic - Arcane → Infernal: Arcane magic reinforces infernal magic - Infernal → Fae: Infernal magic reinforces fae magic - Fae → Divine: Fae magic reinforces divine magic

Core Mechanics: - Mutually Beneficial: One power reinforces the other, and vice versa - Combined Effects: When both systems are used together on the same target or in the same area, they create effects that neither could achieve alone - Potentially Unstable: These combinations can be unstable and spectacular - Potentially Dangerous: May create unexpected results or side effects - Requires Coordination: Typically requires coordination between casters or special class features

Game Mechanics:

Enhanced Spell Effects: When both enhancing systems are used together on the same target or in the same area: - Spell effects may be enhanced beyond normal capabilities (GM discretion or specific spell rules) - Combined spell levels/mana costs determine the strength of the enhanced effect - For mana systems: Add mana costs together - For Fae: Add spell slot levels together - Mixed: Mana cost + spell slot level (they're equivalent) - Enhanced spells may create effects that exceed normal spell capabilities

Unstable Results Table: When combining enhancement systems, roll a d20 to determine stability:

Roll	Result
1-3	Catastrophic Failure: The spell fails catastrophically. Both casters take force damage equal to 1d6 per combined spell level/mana cost
4-10	Unpredictable Side Effects: The spell works but with unpredictable side effects determined by the GM. May include: wild magic surges, additional targets, reversed effects, or temporary conditions
11-17	Successful Enhancement: The spell works as intended with a bonus effect:
- Damage spells: +1d6 bonus damage of appropriate type
- Healing spells: +1d6 bonus healing
- Buff/Debuff spells: +1 to spell save DC or duration increases by 50%
- Utility spells: Enhanced range, duration, or scope
18-20	Spectacular Success: The spell works spectacularly as intended. The enhanced effect is fully realized, potentially with additional benefits determined by the GM. May create effects visible from great distances or with unusually long duration

Special Considerations: - Divine Enhancement: Divine power doesn't count against daily limit when enhancing (but watch instant limit) - Infernal → Fae Enhancement: SAFE - Fae casters can use infernal mana to enhance fae spells without risk of corruption, tolerance checks, or mutations. This is one of the only safe ways to use infernal mana. - Other Infernal Enhancements: Infernal enhancement with other systems (Arcane → Infernal) adds to tolerance check—risk of overuse consequences increases - Arcane Enhancement: Normal mana costs apply - Fae Enhancement: Normal spell slot usage applies

Requirements: - Both systems must be active simultaneously (either two casters coordinating or a multiclass character with both systems) - The enhancing relationship is mutual—both systems benefit from the combination - Requires careful control—unstable combinations can be dangerous

Specific Examples: - Divine + Arcane: - Healing spells restore additional hit points - Protective spells (like Shield of Faith combined with Mage Armor) provide enhanced defense - Damage spells may gain radiant damage component

Arcane + Infernal:
Damage spells deal bonus fire or necrotic damage
Summoning creates more powerful entities
Enchantment spells may have enhanced duration
Infernal + Fae:
Nature-based infernal effects are more potent
Corrupting nature spells have enhanced effects
Wild magic zones may form at the intersection
SAFE COMBINATION: Fae casters using infernal mana suffer no corruption, tolerance checks, or mutations—this is one of the only safe ways to channel infernal power
Fae + Divine:
Nature/divine hybrid spells (like druidic healing) are enhanced
Plants and animals respond more powerfully
Natural areas become more potent

Energy Level Comparisons

Opposite Actions

When opposite spells clash directly, compare the spell levels/mana costs:
Divine vs Infernal: Both use mana—compare mana costs (spell level = mana cost)
Arcane vs Fae: Arcane uses mana cost, Fae uses spell slot level—treat as equivalent (3 mana = 3rd level slot)
Higher energy cost wins automatically
Tied costs: Both spells fail, both casters take damage equal to the spell level
Close contests (within 1 level): Roll d20, 1-5 means victorious spell becomes unstable

Interference

Spell level/mana cost of interfering magic determines the DC for disruption checks
Mana Systems (Arcane, Divine, Infernal): Use spell level (mana cost = spell level)
Fae System: Use spell slot level
DC = 10 + interfering spell level (minimum 10)
No automatic victory—always requires a concentration check

Enhancement

Combined spell levels/mana costs determine enhanced effect strength
Add mana costs together for mana-based systems
Add spell slot levels for Fae
When mixing: Treat mana cost and spell slot level as equivalent
Higher combined levels = more powerful but potentially more unstable results
Both casters must expend resources (mana or spell slots) for the combination to work

Concentration and Interference

Interference Effects on Concentration

Interfering systems can force concentration checks as a reaction when target spell is being cast
This applies to spells being cast, not ongoing concentration spells (unless specifically targeting concentration)
Areas saturated with interfering magic may require concentration checks to cast spells

Area-Based Concentration

Advantage on concentration checks when your spell matches the area's dominant magic system
Disadvantage on concentration checks when your spell opposes the area's dominant system
Normal checks when your spell neither matches nor opposes the area's system

Multiclassing Considerations

Characters who learn multiple magic systems face specific considerations based on interaction types:

Opposing Systems

Characters with opposing systems (e.g., Cleric/Warlock, Wizard/Druid):
Cannot cast both types effectively in the same area without penalties
Must choose which system to use in saturated areas
May face internal conflicts or moral dilemmas
Advantage on saves against their own opposite system when used by others
Must manage separate resource pools (mana pools for Arcane/Divine/Infernal, spell slots for Fae)

Enhancing Systems

Characters with enhancing systems (e.g., Cleric/Wizard, Warlock/Druid):
Can benefit from enhancement combinations
May need to coordinate with themselves (using both action and bonus action, or with reactions)
Require careful resource management:
- Mana Systems: Track mana pools separately
- Fae: Track spell slots separately
- Divine: Watch daily and instant limits
- Infernal: Risk tolerance checks when combining (EXCEPT Infernal → Fae is safe)
Face risk of unstable results when combining systems
Exception: Infernal → Fae combinations are safe—no tolerance checks or corruption risk for fae casters

Interfering Systems

One system may interfere with the other during casting
May need to choose which system to prioritize
Interference doesn't prevent multiclassing, but requires tactical awareness

General Rules

Resource Tracking: Each magic system tracks resources separately:
Arcane: Mana pool (Base Mana + Intelligence Modifier × Caster Level)
Divine: Daily limit (caster level × Wisdom modifier) and instant limit (Proficiency Bonus + Wisdom modifier, or alternate for specific classes)
Fae: Spell slots (half caster progression as default, can be supplemented through roleplay or feats)
Infernal: Tolerance limits (Constitution-based with Intelligence bonus, but unknown to player)
Must track which spells use which system
Opposing systems cause complications in saturated areas
Enhancement combinations are possible but risky
No restriction on multiclassing between systems, but understand the implications
See Mana for detailed resource mechanics per system

Area Magic Saturation

Some locations have strong magic system presence that affects casting:

Arcane-Saturated Areas

Locations: Wizard towers, magical laboratories, arcane research facilities, enchanted cities, magical academies

Effects: - On Fae Magic (Opposite): Disadvantage on spell attack rolls, spell save DC reduced by 2 - On Arcane Magic (Same): Normal casting - On Divine Magic (Interfered): May require concentration checks (DC 10-15) to cast - On Infernal Magic (Enhancement Source): Can enhance infernal magic if combined

Fae-Saturated Areas

Locations: Deep wilderness, fey groves, ancient forests, natural springs, druidic circles

Effects: - On Arcane Magic (Opposite): Disadvantage on spell attack rolls, spell save DC reduced by 2 - On Fae Magic (Same): Normal casting - On Infernal Magic (Interfered): May require concentration checks (DC 10-15) to cast - On Divine Magic (Enhancement Source): Can enhance divine magic if combined

Divine-Saturated Areas

Locations: Temples, holy sites, sanctified ground, shrines, consecrated areas

Effects: - On Infernal Magic (Opposite): Disadvantage on spell attack rolls, spell save DC reduced by 2 - On Divine Magic (Same): Normal casting - On Fae Magic (Interfered): May require concentration checks (DC 10-15) to cast - On Arcane Magic (Enhancement Source): Can enhance arcane magic if combined

Infernal-Saturated Areas

Locations: Demon summoning sites, hell portals, corrupted areas, infernal strongholds, places of great evil

Effects: - On Divine Magic (Opposite): Disadvantage on spell attack rolls, spell save DC reduced by 2 - On Infernal Magic (Same): Normal casting - On Arcane Magic (Interfered): May require concentration checks (DC 10-15) to cast - On Fae Magic (Enhancement Source): Can enhance fae magic if combined

Enhancement Areas

Areas where two enhancing systems are both present may provide bonuses: - Advantage on spell attack rolls for matching systems - +1 to spell save DCs - Extended duration for certain spells - Reduced risk on enhancement combinations (treat unstable results table as if rolling +2)

Spell Modifications

Dispel Magic

Against Opposite System: - Advantage on the ability check - Spell level/mana cost matters—if your dispel uses mana/spell level 2+ levels higher, you have Advantage and the DC is reduced by 2 - For mana systems: Compare mana costs - For Fae: Compare spell slot levels - Mixed: Treat as equivalent

Against Interfering System (when you interfere with them): - Advantage on the ability check - Normal DC otherwise

Against Same System: - Normal ability check - Standard DC calculation

Against Enhancing System: - Normal ability check - However, dispelling may extend the duration of remaining effects from the enhancing system (GM discretion)

Against System That Interferes With You: - Normal ability check - No special benefits

Counterspell

Any caster can attempt to counterspell using their magical resources. Counterspelling has two main applications:

Direct Counterspelling: Countering a spell as it's being cast (reaction during spellcasting)
Disenchanting: Breaking down a standing magical effect or enchanted object (requires time and sustained effort)

Both applications use the same three methods, but effectiveness varies based on the magic system relationship.

Three Methods of Counterspelling

1. Same Magic Type (Skill-Based Counterspell)

Using the same magic system to counterspell is a skill-based approach that relies on understanding and manipulating your own magic system.

Resource Cost: You must expend an equal amount of magical resource (mana cost, spell slot level, etc.) as the target spell/effect.

Mechanics: - Opposed Caster Check: Make an opposed ability check using your spellcasting ability modifier + proficiency bonus vs. the target's spellcasting ability modifier + proficiency bonus - Your roll: d20 + Spellcasting Ability Modifier + Proficiency Bonus - Target's roll: d20 + Spellcasting Ability Modifier + Proficiency Bonus - If you win: The spell/effect is countered or disrupted - If you lose: The spell/effect proceeds normally, but you still expend your resource

Against Direct Spellcasting (reaction): - Moderate Effectiveness: Can counter spells being cast - Timing: Must be used as a reaction when the spell is being cast - Advantage: You understand your own magic system intimately - Disadvantage: Requires matching or exceeding the target's skill

Against Standing Enchantments: - Harder to Use: Standing enchantments have had time to stabilize and integrate - Time Required: Cannot be done as a reaction—requires 1 minute of sustained effort per spell level of the enchantment - Opposed Check DC: The enchantment's "opposed roll" uses the original caster's ability modifier (if known) or a DC equal to 10 + enchantment's spell level × 2 - Success: Enchantment is disrupted or disenchanted - Failure: Enchantment resists, and you may trigger defensive effects

2. Opposed Magic Type (Overloading Counterspell)

Using an opposing magic system (Divine vs Infernal, Arcane vs Fae) creates a violent energy clash that usually causes explosions or major unintended effects.

Resource Cost: You must expend at least as much resource as the target spell/effect. You can expend more for increased chance of success.

Mechanics: - Energy Contest: Compare spell levels/mana costs directly - Automatic Success: If your counterspell uses mana/spell level 2+ levels higher than the target, it automatically succeeds - Advantage on Check: If levels are equal or within 1 level, you have Advantage on an ability check (but still must make the check) - Tied Energy: If exact same level, both fail catastrophically—see Catastrophic Failure below - Opposed Check: Roll your spellcasting ability check with Advantage vs. target's spellcasting ability (no Advantage)

Catastrophic Failure (when exact same level used): - Both spells/effects fail - Both casters take force damage equal to the spell level used (minimum 1) - Explosion or magical backlash occurs in a 10-foot radius - All creatures in area must make Dexterity saving throw (DC 10 + spell level) or take half damage

Unintended Effects: - Close Contests (within 1 level): Roll d20 after resolution: - 1-5: The victorious spell becomes ragged, unstable, and fizzles out uselessly despite winning - 6-15: Spell works but causes unintended side effects (wild magic surge, additional targets, etc.) - 16-20: Spell works normally - Visual Effects: Clashes are flashy, spectacular, and often dangerous to nearby creatures

Against Direct Spellcasting (reaction): - Highly Effective: Opposing magic disrupts and destroys opposing effects - Automatic Success: If you use 2+ levels higher, no check needed - High Risk: Catastrophic failures possible, especially on ties - Timing: Must be used as a reaction when spell is being cast

Against Standing Enchantments: - Overloading Effect: Attempts to overload and destroy the enchantment through pure energy clash - Time Required: Cannot be done as a reaction—requires 1 action per spell level of the enchantment - Explosion Risk: High risk of explosion or magical backlash when disenchanting - Area Effects: May damage nearby objects or creatures when enchantment is destroyed - Success: Enchantment is violently destroyed (may leave residual effects) - Failure: Enchantment resists, explosion may backfire on you

3. Interfering Magic Type (Smothering Counterspell)

Using an interfering magic system (Divine → Fae, Fae → Infernal, Infernal → Arcane, Arcane → Divine) quietly smothers the magical effect by disrupting its stability.

Resource Cost: You must expend at least as much resource as the target spell/effect. Interference doesn't require matching exactly.

Mechanics: - Concentration Check Alternative: Instead of a direct opposed check, you can force a concentration check as a reaction - DC: 10 + your spell level/mana cost (minimum DC 10) - Target: The caster (for direct spells) or the enchantment's stability (for standing effects) - Success: Spell/effect fails or is disrupted - Failure: Spell/effect continues, but interference may still have subtle effects

Gentle Disruption: - Unlike opposite actions, interference doesn't cause violent explosions - The target magic simply becomes unstable and fizzles out - More subtle and less spectacular than opposite action clashes

Against Direct Spellcasting (reaction): - Hardest to Use: Takes time to disrupt magic, but can be attempted as reaction - Concentration Check: Can force concentration check instead of opposed roll - DC: 10 + interfering spell level (use mana cost for mana systems, spell slot level for Fae) - On Success: Target spell fails and target loses their resource - On Failure: Spell continues, but you can still attempt normal counterspell on your next turn - Less Reliable: Not as immediate as opposite actions, but safer

Against Standing Enchantments: - Most Effective: Interfering magic excels at breaking down standing enchantments - Time Required: Requires sustained effort: - Initial Attempt: 1 action to begin interference - Disruption Period: 1 minute per spell level of the enchantment - Concentration Required: You must maintain concentration during the disruption period - Interruption: If you lose concentration, the process fails and you must start over - Quiet Method: Unlike opposite actions, this doesn't cause explosions - No Backlash: Safer than overloading, but requires patience - Success: Enchantment is gently disenchanted, can be salvaged or studied - Failure: Enchantment resists, but no harmful effects to you

Dispel Magic with Interference: - Advantage on ability checks when dispelling spells from a system you interfere with - Can use interference method even when using Dispel Magic spell - More reliable than direct counterspelling for this magic type relationship

Comparison Summary

Method	Direct Counterspelling	Standing Enchantments	Risk Level	Effectiveness
Same Type	Moderate	Hard	Moderate	Skill-based, reliable
Opposed Type	Easy	Moderate	Very High	Explosive, dangerous
Interfering Type	Hard	Easy	Low	Slow but safe

Special Cases

Against Enhancing Systems: - When counterspelling an enhancing system combination, the counterspell may be less effective - GM may rule the enhancement provides resistance or advantage - Best to target one system at a time rather than the combination

Multiclass Counterspelling: - You can use any magic system you know to counterspell - Must expend resources from the appropriate system - Circle of Interaction still applies (can use enhancing systems, but watch for complications)

Spell Resistance

Creatures with divine resistance have Advantage on saves vs. infernal magic
Creatures with infernal resistance have Advantage on saves vs. divine magic
Creatures with arcane resistance have Advantage on saves vs. fae magic
Creatures with fae resistance have Advantage on saves vs. arcane magic
Resistance to one system does not grant resistance to systems that interfere with or enhance it

Examples

Example 1: Divine Cleric vs. Infernal Warlock (Opposite Actions)

Situation: A 5th-level Cleric faces a 5th-level Warlock in an infernal-corrupted area.

Cleric's Turn: Attempts to cast Cure Wounds (1st level, costs 1 mana)
Casting in infernal area: Disadvantage on spell attack (if applicable), spell save DC reduced by 2
Area saturation affects divine magic negatively
Uses 1 mana from daily limit
Warlock Counterspells: Uses Counterspell at 3rd level (costs 3 infernal mana)
Has Advantage on the check (opposite system)
Cleric's 1st level (1 mana) vs. 3rd level (3 mana) counterspell: Warlock has Advantage and likely succeeds
Warlock must make tolerance check for 3 mana infernal spell
Cleric Counterspells Back: Uses Counterspell at 3rd level (costs 3 mana) against Warlock's Eldritch Blast
Has Advantage (opposite system)
If both are 3rd level and tied: Both spells fail, both take 3 force damage
Energy-Based Contest: If Cleric casts Flame Strike (5th level, 5 mana) and Warlock casts Hellish Rebuke (3rd level, 3 mana):
Cleric's spell automatically wins (higher mana cost: 5 vs 3)
Since difference is 2 levels, no ragged victory check needed
If both used 3rd level (3 mana each): Both fail, both take 3 force damage

Example 2: Arcane Wizard vs. Fae Druid (Opposite Actions in Arcane Tower)

Situation: A Druid attempts to cast spells inside a Wizard's tower, which is heavily arcane-saturated.

Druid Casts Entangle: Fae magic in arcane area (uses 1st level spell slot)
Disadvantage on spell attack roll (if applicable)
Spell save DC reduced by 2 (e.g., DC 13 instead of 15)
10% chance of spell failure in heavily enchanted areas
Wizard Counterspells: Uses Counterspell at 3rd level (costs 3 mana)
Has Advantage (opposite system)
Druid's 1st level slot vs. Wizard's 3 mana: Wizard likely succeeds (3 vs 1)
Energy comparison: 3 mana = 3rd level slot, so higher energy wins
Wild Shape: Druid's Wild Shape still works, but:
May be harder to maintain in arcane-saturated environment
Druid feels discomfort while in the area
Fey companions would avoid this location entirely

Example 3: Divine Disrupting Fae Spellcasting (Interference)

Situation: A Cleric and Druid are in the same area. Druid attempts to cast Call Lightning.

Divine Interference: Cleric can use reaction to interfere
Forces concentration check: DC = 10 + Cleric's spell level (if Cleric uses a 2nd level spell costing 2 mana, DC 12)
Druid makes Constitution saving throw against DC 12
On Failure: Call Lightning fails, Druid loses the 3rd level spell slot
On Success: Spell casts normally
Key Point: This is gentler than opposite actions—no energy contest, just disruption
Limitation: Cleric can only disrupt the spell being cast, not an already-active Call Lightning storm
Resource Cost: Cleric expends the mana used for interference (2 mana in this case)

Example 4: Arcane + Infernal Combination Spell (Enhancement)

Situation: A Wizard and Warlock coordinate to enhance a damage spell on the same target.

Wizard Casts Fireball (3rd level, costs 3 mana): Targets enemy group
Warlock Casts Hellish Rebuke (3rd level, costs 3 mana): On same turn, targets same area
Warlock's Tolerance Check: Must make tolerance check for 3 mana infernal spell (Constitution + Warlock level = base tolerance, Intelligence modifier adds to efficiency)
Enhancement Active: Both arcane and infernal magic target same area
Unstable Results Check: Roll d20 (combined spell levels: 3 + 3 = 6)
Roll 4: Unpredictable side effects—GM determines: The fireball explodes with black flames, dealing extra necrotic damage but also creating a temporary zone of despair
Roll 14: Successful enhancement—Fireball deals +1d6 fire damage (4d6 + 1d6 = 5d6 total), and Hellish Rebuke deals +1d6 fire damage
Roll 1: Catastrophic failure—Both spells fail, both casters take 6d6 force damage (combined spell levels: 6)
Roll 19: Spectacular success—The combined magic creates an infernal firestorm that deals enhanced damage and leaves lingering hellfire that burns for 1 additional round
Special Risk: If Warlock exceeds tolerance, roll on Infernal Overuse table in addition to enhancement results
Note: If this were a Fae caster using Infernal mana (Infernal → Fae), there would be NO tolerance check or corruption risk—that combination is safe

Example 5: Multiclass Character Navigating Mixed Environment

Situation: A Cleric 5 / Wizard 5 character in a temple (divine-saturated area).

Casting Divine Spells:
Works normally (same system as area)
Advantage on concentration checks
Casting Arcane Spells:
Normal casting (enhancement relationship)
May benefit from enhancement if combining with divine magic
No penalties
If in Infernal-Corrupted Area:
Divine spells: Disadvantage and -2 DC (opposite system)
Arcane spells: Normal (enhancement source, but no active enhancement without infernal magic)
Character must choose which system to prioritize
Combining Systems:
If character casts Bless (divine, 1st level, 1 mana) and Magic Weapon (arcane, 2nd level, 2 mana) on same target:
Enhancement active: Roll on unstable results table
Combined levels (1+2=3): Risk of 3d6 damage on catastrophic failure
Potential for enhanced effects if successful
Must track both mana pools: Divine mana from daily limit, Arcane mana from arcane pool

House Rules

[Any campaign-specific modifications to these interactions can be noted here]

Optional Rule: Skill Matters for Close Contests

Some GMs may wish to allow skill to matter in opposite action contests when spell slots are very close: - If spell slots differ by only 1 level, the caster with higher spellcasting ability modifier gains Advantage on a contested roll - Roll opposing d20s: Higher roll wins, but still risks ragged victory on low rolls

Optional Rule: Interference Requires Line of Sight

For interference to work, the interfering caster must be able to see or sense the target spell being cast. This prevents interference through walls or at extreme distances.

Optional Rule: Enhanced Spell Combinations

Some GMs may create specific spell combinations that work particularly well together when using enhancement systems. These can be treated as special "combo spells" that reduce the risk of unstable results.