Ominous Shroud (Ability ID: 822)

Short Description: Phantom + Shadow Shield.

Extended In-Game Description

Ominous Shroud grants the Pokémon Ghost typing upon entering battle, even if it wasn't Ghost-type originally. Additionally, when at full HP, the Pokémon takes only 50% damage from all attacking moves. This defensive bonus is lost when the Pokémon's HP drops below maximum, but the Ghost typing remains permanent throughout battle.

Character count: 295

Mechanical Implementation

Ominous Shroud is a combination ability that merges two distinct effects:

Phantom Component (onEntry)

• Function: Adds Ghost type to the Pokémon upon entering battle
• Implementation: AddBattlerType(battler, TYPE_GHOST)
• Effect: The Pokémon gains Ghost typing as a third type (stored in type3 slot)
• Persistence: Remains active throughout the entire battle
• Interaction: Only adds Ghost type if the Pokémon doesn't already have it

Shadow Shield Component (onDefensiveMultiplier)

• Function: Reduces incoming damage by 50% when at full HP
• Implementation: if (BATTLER_MAX_HP(battler)) MUL(.5)
• Condition: Only active when the Pokémon is at maximum HP
• Breakable: Yes - this defensive bonus can be negated by Mold Breaker-like abilities

Battle Interactions

Type Addition Mechanics

1. Ghost Type Addition: Immediately upon entering battle, the Pokémon gains Ghost typing
2. Type Immunities: Gains immunity to Normal and Fighting moves (standard Ghost-type immunity)
3. Type Weaknesses: Becomes weak to Ghost and Dark moves
4. STAB Bonus: Can now receive STAB on Ghost-type moves if learned

Damage Reduction Mechanics

1. Full HP Requirement: Must be at exactly maximum HP for damage reduction
2. All Move Types: Affects physical, special, and status moves that deal damage
3. Multiplicative Reduction: 50% damage reduction applies after type effectiveness calculations
4. Loss Condition: Any HP loss removes the defensive bonus until HP is restored to maximum

Strategic Applications

Offensive Benefits

• STAB Ghost Moves: Enhanced Ghost-type move damage if the Pokémon learns them
• Type Coverage: Access to Ghost-type immunities and resistances

Defensive Benefits

• Initial Bulk: Extreme durability on the first hit received
• Switch-In Safety: Safer entry against predicted attacks
• Setup Opportunities: Can survive strong attacks while setting up

Counterplay

• Multi-Hit Moves: First hit removes damage reduction, subsequent hits deal full damage
• Residual Damage: Entry hazards, weather, or status conditions remove the damage reduction
• Mold Breaker: Abilities that ignore opponent abilities negate the damage reduction component
• Ghost/Dark Coverage: The added Ghost typing creates new weaknesses to exploit

Related Abilities

• Phantom: Provides only the Ghost-type addition component
• Shadow Shield: Provides only the damage reduction at full HP component
• Multiscale: Similar damage reduction mechanic (Shadow Shield is based on Multiscale)
• Disguise: Another defensive ability that prevents damage, but works differently

Pokémon Distribution

This ability is designed for Pokémon that benefit from both defensive bulk and Ghost-type properties, typically used on bulky setup sweepers or defensive pivots that can leverage the temporary damage reduction.