Magic Damage Reduction Modification vs. Frame-Based Attacks

Initial report by Jarulf
Compiled by Tommi Gustafsson

What's the deal?

Blizzard has implemented a modifier, which reduces the protective effect of Magic Damage Reduced by X (MDR) against certain continuous attacks (i.e. frame-based attacks), such as Firewall. Blizzard apparently thought that MDR was too powerful against frame-based attacks, and consequently, they reduced its effect as if it was applied once each second instead of once each frame. In many cases, this means that the effect MDR is effectively cut to one-25th. Fortunately, not every frame-based attack has a MDR modifier. Only the ones that are listed in the table below have them. The list does not include, for example, Diablo's Lightning Breath of Death.

**MDR Modifiers**
Attack	MDR Modifier*	MPQ Name
Arctic Blast, Druid	1/25	ArcticBlast1, ArcticBlast2
Armageddon Fire, Druid	1/25	ArmageddonFire
Firestorm, Diablo (twisting fire lines)	1/25	DiabWall
Firestorm, Druid	1/25	FireStorm
Firewall, Countess	1/25	CountessFirewall
Firewall, Sorceress	1/25	Firewall
Firewall, Vampire	1/25	VampireFirewall
Immolation Arrow Fire, Amazon	1/25	ImmolationFire
Inferno, Fetish	2/25 or 1¹⁾	FetishInferno1, FetishInferno2
Inferno, Sorceress	2/25	InfernoFlame1, InfernoFlame2
Meteor Fire, Catapult	1/25	CapapultMeteorFire
Meteor Fire, Sorceress	1/25	MeteorFire
Molten Boulder Fire, Druid	1/25	MoltenBoulderFirePath
Wake of Fire, Assassin	5/25	Wake of Destruction maker, Wake of Destruction
Wake of Inferno, Assassin	2/25	Inferno Sentry 1, Inferno Sentry 2

*) Due to precision, 1/25 is actually 41/1024. Similarly 2/25 is really 82/1024, etc.
1) No reduction against FetishInferno2. In MPQs, full damage is denoted as 0, not 1.

Three Flames of Firewall

The damage of firewall attacks is dealt by three flames that hit the target at the same time. Each flame is a separate attack and hence MDR is applied 3 times. Thus, MDR effectively functions at triple normal power against firewalls.