# ItemModeEffect

> Kinbarrow modding reference — content tree `4a103dcdb658a75a`, version `0.2.0+main.e011511f4`.

[Effects and mechanisms](https://kinbarrow.com/modding/latest/mechanisms.md)

Used by [MagicItem](https://kinbarrow.com/modding/latest/magic-item.md#item-mode-effect).

This is a nested shape inside a content file. The catalog explains context validation and links real RON examples.

A reusable effect projected only by a selected, eligible item mode.

<a id="item-mode-effect--condition-grant"></a>

## ItemModeEffect::ConditionGrant

Project one registered condition from this exact item-mode source.

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `condition` | `string` | required |  |

<a id="item-mode-effect--weapon-hit-damage"></a>

## ItemModeEffect::WeaponHitDamage

A separate typed damage instance on hits with this exact weapon.

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `damage` | `Damage` | required | Dice and damage kind resolved through the ordinary damage ladder. |
| `doubles_on_crit` | `boolean` | required | Whether a critical hit doubles this rider's dice. |

<a id="item-mode-effect--weapon-hit-save-damage-condition"></a>

## ItemModeEffect::WeaponHitSaveDamageCondition

On a hit with this exact weapon, one save gates both typed damage and a timed condition. The rider is not part of critical-hit dice.

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `condition` | `string` | required |  |
| `damage` | `Damage` | required |  |
| `duration_secs` | `uint32` | required |  |
| `save` | `NaturalAttackSave` | required |  |

<a id="item-mode-effect--weapon-damage-kind"></a>

## ItemModeEffect::WeaponDamageKind

Replace this exact weapon's ordinary damage kind while the mode is selected. Dice and modifiers are unchanged; each attack still resolves through the ordinary resistance/immunity ladder for the selected kind.

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `kind` | `string` | required |  |

<a id="item-mode-effect--illumination"></a>

## ItemModeEffect::Illumination

Bright light plus an additional dim-light radius emitted by the item.

Carries `MagicItemIllumination`.

<a id="item-mode-effect--virtual-equipped-arm"></a>

## ItemModeEffect::VirtualEquippedArm

Project one ordinary arm through the concrete magic item. The item must itself satisfy the mode's custody requirement; weapon projections may add properties and alternate proficiency families without duplicating the base weapon definition.

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `base_arm` | `string` | required |  |
| `proficiency_aliases` | `string[]` | default `[]` |  |
| `weapon_properties` | `WeaponProperty[]` | optional |  |

<a id="item-mode-effect--reaction"></a>

## ItemModeEffect::Reaction

Offer an explicit event-local Reaction while this exact mode is active.

Carries `MagicItemReaction`.

<a id="item-mode-effect--walking-speed-multiplier"></a>

## ItemModeEffect::WalkingSpeedMultiplier

Multiply the bearer's complete world-level walking Speed. The ratio is applied after additive/floor sources and before contextual impediments.

| Field | Type | Required | Description |
| --- | --- | --- | --- |
| `denominator` | `uint32` | required |  |
| `numerator` | `uint32` | required |  |

<a id="item-mode-effect--opportunity-disadvantage"></a>

## ItemModeEffect::OpportunityDisadvantage

Attacks made specifically as Opportunity Attacks against the bearer have Disadvantage; ordinary attacks are unchanged.


## Supporting shapes

- [Damage](https://kinbarrow.com/modding/latest/magic-item.md#damage)
- [MagicItemIllumination](https://kinbarrow.com/modding/latest/mechanisms/magic-item/magic-item-illumination.md)
- [MagicItemReaction](https://kinbarrow.com/modding/latest/mechanisms/magic-item/magic-item-reaction.md)
- [NaturalAttackSave](https://kinbarrow.com/modding/latest/mechanisms/magic-item/natural-attack-save.md)
- [WeaponProperty](https://kinbarrow.com/modding/latest/class-def.md#weapon-property)