When the Pokémon takes damage from a Dark-type move, its Attack stat is boosted by 1 stage.
Justified (Japanese: せいぎのこころHeart of Justice) is an Ability introduced in Generation V.
Effect
In battle
When a Pokémon with Justified is hit by a Dark-type damaging move, its Attack is increased by one stage. This Ability does not provide immunity or reduction to the damage, nor does it activate from a Dark-type move hitting its Substitute. Dark-type multistrike moves (such as Beat Up) will activate Justified once per strike, increasing the Attack stat that many stages.
When Gallade gets hit by a Dark-type move, orange energy bursts out of his chest, and he becomes surrounded by an orange aura. Then, his arm blades glow longer than usual and become wrapped in ribbon-like tendrils of orange energy, increasing his attack power.