Unique: Your area of effect abilities (summoner and item abilities excluded) reduce your target's magic resistance by 6, your single target abilities (summoner and item abilities excluded) reduce your target's magic resistance by 12 for 4 seconds (maximum 24 MR-shred) (debuff applies only to enemy units).
Unique: Your area of effect abilities (summoner and item abilities excluded) reduce your target's magic resistance by 6, your single target abilities (summoner and item abilities excluded) reduce your target's magic resistance by 12 for 4 seconds (maximum 24 MR-shred) (debuff applies only to enemy units).
Unique: Throws an etheral orb at the target champion, which instantly applies 2 stacks, additionally the target's magic resistence will be reduced by 0.5% of the target's maximum health. (650 range, 40 seconds cooldown)
Staff of Delusion debuff counts per target, so the same enemy can only have applied 3 stacks of the debuff even when hit by multiple holders of the item.
The very first ability does not get the benefit of the armor reduction. Magical damage from the ability is calculated first, and the debuff is applied after. This means the full benefit of the reduction is seen on the 3rd hit after all 2 debuffs have been applied.
FAQ
The buff won't be applied, if the target is an ally or self (Taric's Imbue)
The buff wont be applied, by toggle abilities (such as Singed's poison trail)
The buff will only be applied once per cast, DoT-effects will apply the buff only once (Morgana's Tormented Soil, Karthus' Defile).
The AP Version of Black Cleaver is not Malady (Malady is the Hybrid Version of BC), since Malady gives Attack Speed (Mages cant make use of this stat), further more the way to trigger the Magic Resistance Shred is not in the favor of Mages either, since they have to auto attack for 4 times till they can make full use of the Shred.
The AP Version of BC is not Abyssal Scepter either, Abyssal Scepter debuffs the targets and is an AoE Magic Resistance reduction, the AD equivalent would be Stark's Fevor, but this item has been removed from the game (it might be reintroduced someday)
Would you like to see Staff of Delusion in the League?