Star Wars: Knights of the Old Republic/Difficulty Classes

Just as the success of a weapon attack in combat is determined by an attack roll against defense, the success or extent of various other damaging, debilitating and status-altering effects is determined by a saving throw against the Difficulty Class (DC) of those effects: the defender makes an opposed roll using d20 + the relevant save (Fortitude, Reflex or Will) versus the attacker's DC. If the saving throw is greater (or equal), then its success may reduce any effect, or even negate it entirely; if it fails, the attack has full effect.

Thus a saving throw always fails if DC > save + 20 (maximum d20 roll), and always succeeds if DC ≤ save + 1 (minimum d20 roll). Otherwise, the chance of success is as follows:

For example, a Fortitude saving throw must normally be made at DC 30 if a is triggered: Fortitude save 9 or less means this throw always fails (maximum 20 + 9 = 29), always resulting in poisoning; however, if it's 19 then it succeeds 50% of the time (roll (11-20) + 19 = 30-39); and if it's 29 or more then it always succeeds (minimum 1 + 29 = 30), never resulting in poisoning.

Feats
If an attack with or  hits, the target is stunned for 6 seconds unless they make a Fortitude save at the following DC:

The target isn't stunned until the end of the attack round. This effect can also be negated by Immunity: or : Stun.

Force powers
Almost all offensive ../Force powers/ have DC 5 + attacker level + attacker and  modifiers + :

Affliction has DC 20, Plague has DC 100 and no saving throw can be made against Force Suppression and Breach, or (Advanced) (although  and Improved  can reduce energy damage).


 * Stun and Fear, Horror and Insanity can also be countered by Immunity: or : Stun.


 * Stasis (Field) can also be countered by : Paralysis.


 * Affliction and Plague can also be countered by Immunity:.


 * Shock, Force Lightning and Storm can also be countered by : Resist #/- vs. Electrical and : 100% vs. Electrical.

All except Force Suppression, Force Breach and (Advanced) Throw Lightsaber can also be countered by Force Resistance or Immunity. Enemies with these powers may be encountered in the following locations (highest attacker and power levels and DCs only):

Grenades
reduces grenade DCs by 2, while Uncanny Dodge 2 reduces them by 4. A successful saving throw halves damage (rounded down) and results in no secondary effect for all but Thermal Detonators.


 * Concussion Grenades can also be countered by Immunity: or : Stun.


 * CryoBan Grenade Paralyzation can also be countered by : Paralysis.


 * Poison Grenades can also be countered by Immunity: or neutralized afterwards by an  or Heal, while damage can also be significantly reduced or even negated by Improved  and.

Mines
../Mines/ can be avoided if you or your party make a successful check to detect them, then move around them or use  to disable or recover them. Otherwise:

A successful saving throw results in no effect for flash and gas mines, but only halves damage of frag and plasma mines.


 * Flash mines can also be countered by Immunity: or : Stun.


 * Gas mines can also be countered by Immunity: or neutralized afterwards by an  or Heal, while damage can also be significantly reduced or even negated by Improved  and.

On Hit
On Hit properties only apply their effects upon a successful attack roll to a single target, but these effects can be reduced or even negated if a saving throw is equal to or greater than Difficulty Class (some can also be negated by or, removing the need for a saving throw).

Attribute Damage Dexterity
Targets have their attribute reduced by 1 for 30 seconds unless they make a Reflex save at DC 14. This effect stacks, and is a property of all sonic pistols and rifles. Enemies with these weapons may be encountered in the following locations:

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Horror
Targets have 100% chance to be debilitated with fear for 3 seconds unless they make a Fortitude save at the DC. This effect can also be negated by Immunity: or : Fear, and is a property of the following:

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Advanced Flame Thrower has Reflex Save: DC20 vs damage, but Fortitude Save: DC15 vs Horror.

Enemy droids with these weapons may be encountered in the following locations:

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Instant Death
Targets are killed instantly unless they make a Fortitude save at DC 100, which is impossible without cheating: do not put yourself in a position where you can get hit! Enemies with this property may be encountered in the following locations:

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Paralyze
Targets have a chance to be paralyzed unless they make a Reflex save at the DC. This effect can be negated by : Paralysis, and is a property of the following:

Enemy droids with these weapons may be encountered in the following locations:

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Poison
Targets suffer damage or weakness unless a Fortitude save is made at the DC. Damage is suffered every 3 seconds for 30 seconds, while weakness results in the temporary but increasing loss of the six physical attributes for 36 or 72 seconds.

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Both damage and weakness can also be negated by Immunity: or neutralized afterwards by an  or Heal, while damage can also be significantly reduced or even negated by Improved  and. These effects are properties of the following:

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Enemies with this property may be encountered in the following locations:

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Slowed
Targets have a chance to be slowed for 9 seconds unless they make a Reflex save at the DC. Being slowed reduces movement speed and inflicts -4 Defense, and these effects stack (although duration does not).

This is a property of the following:

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Enemy droids with these weapons may be encountered in the following locations:

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Stun
Targets have a chance to be stunned unless they make a Will save at the DC. This effect can also be negated by Immunity: or : Stun, and is a property of the following:

Enemies with these weapons may be encountered in the following locations:

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Special weapons
Damage is halved if a Reflex save is made at the DC.

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Enemy droids with these weapons may be encountered in the following locations:

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actually inflict energy damage so an Advanced Flame Thrower can inflict the most heat or fire damage in the game (just as a Carbonite Projector Mark II can inflict the most cold damage) although, as can be seen, enemy droids that use them against you are extremely rare.

These droids can be prevented from using their weapons by debilitating them first using a power; otherwise, any combination of a high Reflex save,, (Improved)  and  can significantly reduce or even negate damage entirely (Reflex > 13 and (Improved) Energy Resistance alone guarantee this for normal Flame Throwers and Carbonite Projectors).