There has been a great deal of discussion about defense and its applications.  Some players believe that defense is completely pointless, while others believe that Buy Diablo 2 Resurrected Items can be extremely beneficial.  Based on my online observations, I've discovered that many people desire a high level of defense, but are unaware of what that level of defense entails.

Because I couldn't find a comprehensive source of defense information, I decided to compile everything I could find and put buy D2R items all together in this guide.  I don't claim to be an expert on the game, and I'm confident that this guide will not provide much new information for many of you who are already familiar with it.  Other guides have provided some of the information, but the majority of Diablo 2 Resurrected Items comes from my own research, testing, and speculation.

Please keep in mind that I have limited experience with assassin and Druid builds, so I will not be referring to them extensively.

1.  Defense-related facts and figures

It has no direct effect on reducing damage.

This is something that many of us are aware of.  This is one of the "missing" features of Diablo's defense that many players have complained about.  When a monster attacks you, no matter how much defense you have, you will suffer the same amount of damage.

When running, you must be on your guard.
While diablo 2 resurrected items for sale is commonly believed that when running, defense equals zero, this is not the case.  The game's actual mechanism is that the to/hit formula is completely ignored, and any attack with a chance of hitting you will do damage regardless of whether you are running or not.

What makes the difference is that by ignoring the to/hit calculation, other factors such as CLVL and MLVL are not taken into consideration.  When faced with a running high level character, low level monsters that would normally miss a naked high level character standing still are more likely to hit that same character (even if he or she is dressed in heavy armor).

You must walk, stand, or attack in order to reap the benefits of defense.

2.  What the Department of Defense does

Defending against a physical attack that employs Attack Rating decreases the likelihood of a successful attack.

If you move your mouse cursor over the defense rating number, you will see that chance represented as a percentage.  A new calculation is performed each time you hit or are struck by a monster. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . To see what percentage of the time a zombie will hit you, simply hit a zombie and the game will calculate the percentage.

Some physical attacks (such as Smite and guided arrow) are of the Ignore Target's Defense type, which means that defense will not protect you from them.
Defense and special damage are two types of damage.
Defense has no effect on attacks that are elemental, poisonous, or magical in nature.

If, on the other hand, Skeleton archers fire fire arrows at you and the defense blocks the arrow, you will not suffer any damage from the fire.

3.  How does the defense function?
%Possibility of/hit
The Possibility of HittingFormula with a large number of examples:
The following is the formula that is used to determine the likelihood of being hit:The following is an excerpt from the Dracoy & Co.  Facts and Formulae Archive:

The probability of being hit is equal to 100 * AR / (AR + DR). * 2 * alvl / (alvl + dlvl) / (alvl + dlvl)

AR stands for Attack Rating; alvl stands for Attacker Level; dlvl stands for Defender Level; DR stands for Defense Rating.

So, for example, consider a character at level 85 and a Death Lord (also at level 85).  In contrast, the monster has 6134 AR (as determined by the arreat summit), while the character has 2000 defense.

Calculate the chance of being hit by 100 * 6134 / (6134 + 2000). * 2 * 85 / (85 + 85) = 75% of the total

If you double your defense (for example, with a lvl 1 shout or an armor shrine), the percentage of time you will be hit becomes:The probability of being hit is equal to 100 * 6134 / (6134 + 4000). * 2 * 85 / (85 + 85) = 61% of the total

As you can see, playing double defense does not necessarily imply a 50% chance of being hit.

Increasing your level and fighting the same monster at lvl 90 with the same defense increases your chance of being hit by a monster by a certain percentage. 100 * 6134 / (6134 + 2000) * 2 * 85 / (85 + 90) = 73% of the time you will get hit.

Now, if you double your defense, the chance of being hit drops to: Chance to be Hit = 100 * 6134 / (6134 + 4000) * 2 * 85 / (85 + 90) = 59% Chance to be Hit

Consequently, this chance is significantly influenced by a character's level, monster level, character defense, and monster's attack rating.

For the sake of argument, and because Act 2 defiance mercs are extremely popular, I'll use the example of Act 2.  Consider what that merc can do for us in the scenario described previously.

At lvl 85, an Act 2 defiance merc hired from Normal will provide a 240% boost (slvl 18 Defiance) in combat.  As a result, the percentage to be reached is:

In our initial example with no merc, the chance of being hit was 75%.  Using the formula 100 * 6134 / (6134 + 2000*3. 4) * 2 * 85 / (85 + 85), the chance of being hit was 47%.

Essentially, this means that the monster will only hit you one out of every two swings, rather than three out of every four swings.  The chances of winning increased by approximately 33% (33% of 75 is 25, and 75 – 47 = 25).

Now, to compare with the example at lvl 90 and double defense, consider the following:

In the absence of merc, the chance of being hit is 100 * 6134 / (6134 + 2000*4. 4) * 2 * 85 / (85 + 90) = 40% (as opposed to 59% without merc).

Chances of winning increased by nearly 33% (33% of 59 =20, and 59 – 40 =20).