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The modifier handler system allows you to create stackable buffs and debuffs that dynamically modify spell behavior. Perfect for implementing item systems, talents, or temporary power-ups similar to Risk of Rain.

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Overview

Modifiers are metaskills that trigger at specific points in the spell lifecycle. They can:
  • Modify spell variables (damage, cooldown, range, etc.)
  • Execute custom logic on spell cast, damage, or cooldown events
  • Stack multiple times for increased effect
  • Be dynamically added or removed during gameplay
  • Have priority-based execution order

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How It Works

The modifier system uses a map-based architecture:
  1. Modifiers are stored in caster.modifier_map with their parameters
  2. When triggered, modifiers are filtered by trigger type
  3. Filtered modifiers are sorted by priority (highest first)
  4. Each modifier metaskill executes in order
modifier_handler.yml:118
modifier-trigger:
  Skills:
  - return ?!varisset{var=caster.modifier_list}
  - skill{s=modifier-parse_list}  # Filter and sort by trigger
  - skill{s=modifier-execute}     # Execute in priority order

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Adding Modifiers

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modifier_name
string
required
Unique identifier for this modifier. Used for removal and stacking.
modifier_name="Blazing Sun"
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o
metaskill
required
The metaskill to execute when this modifier triggers. Cannot be inline - must reference a skill ID.
o=modifier-blazing_sun
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trigger
string
default:"PRECAST"
When this modifier should execute. Available triggers:
  • PRECAST - Before spell evaluation
  • PRE_CAST - Before spell execution
  • CAST - After spell cast
  • PRE_DAMAGE - Before damage calculation
  • DAMAGE - After damage dealt
  • WEAPON_HIT - On melee weapon hit
  • ABILITY_HIT - On ability hit
  • CRITICAL_DAMAGE - On critical hit
  • COOLDOWN_END - When cooldown expires
  • COOLDOWN_RESET - When cooldown manually reset
trigger=CAST
​
priority
integer
default:"1"
Execution order - higher priority executes first. Priority levels:
  • 1 - LOWEST
  • 2 - LOW
  • 3 - MEDIUM
  • 4 - HIGH
  • 5 - SPELL SELECT
  • 6 - SPELL EXECUTION
  • 7 - MONITOR
priority=7
​
stacks
integer
default:"1"
Numerical parameter for stacking modifiers. Can be used to scale effects within the modifier metaskill.By default, stacks will not override unless new stacks > old stacks.
stacks=5

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Basic Example

Add a damage-boosting modifier that reduces warmup:
modifier_handler.yml:254
blazing_sun-exec:
  Skills:
  - skill:modifier{modifier_name="Blazing Sun";o=modifier-blazing_sun} @self

modifier-blazing_sun:
  Skills:
  - setvar{var=caster.blazing_sun;val=<caster.var.blazing_sun|3>-1} @self
  - variableMath{var=damage;equation='x*20'}      # 20x damage boost!
  - variableMath{var=warmup;equation='x*0.2'}    # 80% faster cast
  - sound{s=peachtree:spellbound_battlemage.castshort;pitch=1;volume=3} @self
  
  - skill{s=modifier-blazing_sun-remove}

modifier-blazing_sun-remove:
  Conditions:
  - varinrange{var=caster.blazing_sun;val=<1}
  Skills:
  - variableUnset{var=caster.blazing_sun}
  - skill{s=modifier-remove;modifier_name=Blazing Sun}

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Triggering Modifiers

Manually trigger modifiers at any point: 
my_spell:
  Skills:
  - skill{s=modifier-trigger;trigger=PRE_CAST} @self
  - damage{a=<skill.var.damage>} @target
  - skill{s=modifier-trigger;trigger=CAST} @self
The spell handler automatically triggers modifiers at key points:
spell_handler.yml:54
spell-execute:
  Skills:
  - skill{s=modifier-trigger;trigger=PRE_CAST}
  - skill{s=spell-critical}
  - skill{s=spell-select}

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Removing Modifiers

Remove by name: 
modifier-remove:
  Skills:
  - skill{s=modifier-remove;modifier_name=Blazing Sun} @self
Clear all modifiers: 
modifier-clear:
  Skills:
  - skill{s=modifier-clear} @self

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Stacking System

Modifiers with the same name can stack. Use the stacks parameter to scale effects:
modifier_handler.yml:247
modifier-test3:
  Skills:
  - skill:modifier{o=avarice;modifier_name="Avarice";trigger=something;priority=9;stacks=9} @self
  - skill:modifier{o=avarice;modifier_name="Avarice";trigger=something;priority=9;stacks=3} @self
  # Only the 9 stack version is kept (9 > 3)
Access stack count in your modifier: 
modifier-avarice:
  Skills:
  - variableMath{var=damage;equation='x*(1+<caster.var.modifier_map.avarice.tolist.3>*0.1)'}  # +10% per stack

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Risk of Rain Style Items

Create a modular item system where items add modifiers: 
item-lens_makers_glasses:
  Skills:
  - skill:modifier{modifier_name="Lens-Maker's Glasses";o=modifier-lens_makers;
    trigger=PRE_CAST;priority=6;stacks=1} @self

modifier-lens_makers:
  Skills:
  # Get stack count from modifier map
  - setvar{var=stacks;val=<caster.var.modifier_map.modifier-lens_makers.tolist.3>}
  # +10% crit chance per stack
  - variableMath{var=critical_chance;equation='x+(<skill.var.stacks>*0.1)'}

item-crowbar:
  Skills:
  - skill:modifier{modifier_name="Crowbar";o=modifier-crowbar;
    trigger=PRE_DAMAGE;priority=5} @self

modifier-crowbar:
  Skills:
  # Deal 75% more damage to targets above 90% health
  - return ?comparevalue{v1=<target.hp>;op=<;v2=<target.mh.mul.0.9>}
  - variableMath{var=damage;equation='x*1.75'}

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Modifier Chain Example

Multiple modifiers executing in priority order:
modifier_handler.yml:232
modifier-test2:
  Skills:
  - skill:modifier{o=avarice;modifier_name="Avarice";trigger=something;priority=9} @self
  - skill:modifier{o=burst;modifier_name="Burst";trigger=something;priority=7} @self
  - skill:modifier{o=blazing_sun;modifier_name="Blazing Sun";trigger=something;priority=7} @self
  - skill:modifier{o=phanon;modifier_name="Phanon";trigger=something;priority=6} @self
  - skill:modifier{o=sunfire_lance;modifier_name="Sunfire Lance";trigger=something;priority=6} @self
  - skill:modifier{o=lazarus;modifier_name="Lazarus";trigger=something;priority=3} @self
  - skill:modifier{o=reconsolidation;modifier_name="Reconsolidation";trigger=something;priority=7} @self
  
  - skill:modifier-trigger{trigger=something} @self
  # Execution order: Avarice(9) → Burst(7) → Blazing Sun(7) → Reconsolidation(7) → 
  #                  Phanon(6) → Sunfire Lance(6) → Lazarus(3)

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Temporary Modifiers with Auras

Combine modifiers with auras for temporary buffs:
modifier_handler.yml:280
sunfire_lance-exec:
  Skills:
  - skill:modifier-add{modifier_name="Sunfire Lance";type=STRIKE;trigger=CAST;o=modifier-sunfire_lance} @self

modifier-sunfire_lance:
  Skills:
  - aura{modifier_name=sunfire_lance;d=2*20;i=1;ma=true;rd=false;bt=true;bartimertext=Sunfire Lance;
    oe=[ 
      - skill{s=modifier-remove;modifier_name=Sunfire Lance}  # Auto-remove after 2 seconds
      ]} @self

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Important Warnings

DO NOT call modifier-add or modifier-trigger within a modifier metaskill itself. This can cause infinite loops or unexpected behavior.
# ❌ BAD - Creates infinite loop
modifier-bad:
  Skills:
  - skill:modifier{modifier_name="Another";o=something} @self

# ✅ GOOD - Modifiers should only modify variables
modifier-good:
  Skills:
  - variableMath{var=damage;equation='x*2'}

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Advanced: Insertion Sort

Modifiers are sorted using insertion sort for deterministic ordering:
modifier_handler.yml:163
modifier-insertion_sort:
  Skills:
  - setvar{var=list;val=<skill.list>;type=list}
  - setvar{var=list_size;val=<skill.var.list.size>;type=INTEGER}
  - setvar{var=order;val=<skill.order|asc>;type=STRING}  # "asc" or "desc"
  - return ?comparevalue{val1=<skill.var.list_size>;op=<=;val2=1}
  
  - foreachvalue{skill=modifier-sort_insert;values=<skill.list>}

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Debugging

Enable debug mode to see modifier execution: 
- setvar{var=debug;val=true;type=STRING}
- skill:modifier-trigger{trigger=CAST} @self
# Shows: "Collected <modifier_list>" and "Executing <modifier_name>"

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Map Data Structure

Modifiers are stored in this format: 
modifier_map:
  operation_name: [modifier_name, trigger, priority, stacks]

Example:
  modifier_map:
    modifier-blazing_sun: ["Blazing Sun", "PRECAST", 7, 1]
    modifier-avarice: ["Avarice", "CAST", 9, 5]

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