In general terms, resistance to an effect reduces its potency but does not make it less likely to occur.
- Resistance to damage reduces the amount of damage suffered. Tankers and Brutes can get up to 90% resistance to any type of damage, Kheldians and Soldiers of Arachnos can get up to 85% resistance to any damage type, and all other archtypes can get up to 75% damage resistance to any damage type.
- Resistance to a debuff reduces the amount of the debuff.
- Resistance to knockback reduces the knockback distance.
- Resistance to a Status Effect causes that status to wear off faster.
- Note: Many powers are described in the game as providing Resistance to knockback or status effects when they actually provide Protection.
Resistances to damage and debuffs follow the formula
- SufferedAmount = AppliedAmount × (100% – TotalResistance)
For example, 75% resistance to fire damage would stop 75% of all fire damage that hostile powers try to apply to a character, allowing only 1/4 of it to affect him or her.
Resistance to status effects follows a different formula:
- SufferedDuration = AppliedDuration / (100% + TotalResistance)
So 75% resistance to Sleep duration, for example, would not cause all Sleeps to affect the character for only 1/4 of their normal durations. Their durations would be divided by 1.75, which is roughly only a 43% reduction.
More importantly, the formula means that achieving 100% or more resistance to effect durations does not cause them to end instantly. 100% resistance actually only cuts their durations in half, 200% cuts it to a third, 300% would cut it to a fourth, and so on.
Resistance to Resistance Debuffs
Resistance to resistance debuffs follow the formula
- NewResistance = OriginalResistance + DebuffAmount - [(DebuffAmount × OriginalResistance) / 100%]
In other words, resistance resists resistible resistance debuffs. As confusing as that sentence is, it accurately describes how resistance debuffs are applied. To clarify, lets look at an example: An Invulnerability Tanker has +45% Lethal Resistance and +20% Energy Resistance. This Tanker is hit with a Corruptor's Enervating Field. Enervating Field applies a -22.5% resistance debuff to all damage types. How much will the Tanker resist Lethal attacks? Energy attacks?
To answer this, we need to know how much of that -22.5% resistance will be resisted. Since Enervating Field is resistable, we know that it will be resisted by the resistance value it is debuffing. Since Damage types are independent of one another it is necessary to calculate the new resistance debuffs separately. In this case the Tanker would end up with 32.625% Lethal Resistance and 2% Energy Resistance. Though this might seem to make it difficult to gauge the usefulness of resistance debuffs, it is important to note that this Tanker will still take 22.5% more damage from all attacks. Example: an attack dealing 100 Smashing damage would only deal 55 damage to the undebuffed Tank, but will deal 67.375 points of damage to the debuffed tank. 67.375 is exactly 22.5% more than 55.
It's also important to remember that stacked resistance debuffs always use the undebuffed resistance value when calculating resistance. This way there can be no cascading resistance failures. In this example, if another Corruptor applied a second Enervating Field, the poor Tanker would resist the Lethal resistance debuff component by 45% and the Energy resistance debuff component by 20%.