Player vs. Player combat is a controversial element of play in Diablo II. Some players eschew it entirely and would prefer that PVP was removed from the game. Others only kill monsters to item find and level up their PVP characters. Others are the dreaded "PKs" (Player Killers) who might enjoy dueling, but mostly enjoy attacking and trying to kill unsuspecting players, or players who do not want to duel.

Wherever you fall on this spectrum, you need to know the rules and regulations of PvP, if you're going to play on Battle.net.

Enabling PVP

By default, there is no way to damage other players in Diablo II. There is no "friendly fire" in the game, and you can shoot arrows or swing your sword through other players and their minions, or cast spells in every direction, without ever hurting any friendly or neutral players, or their minions. If you want to damage someone else, you have to declare hostility, or have it declared on you. See the Multiplayer page for full details on that process.

To declare hostility a character must above level 9, and be in town. Once there, open the party window and click the crossed swords icon beside the name of the character you wish to fight (they must be over level 9 as well). You will immediately go hostile to them and anyone in their party, and they will hear a warning horn blare and see an on-screen notification of your challenge. They will go hostile to you at the instant you declare it on them (so they can fight back). The character who declares hostility will see their town portal close, and be unable to use any other player's town portal (a feature added to make quick ambushes more difficult).

To remove hostility and return to a friendly setting, both players must agree. If one player turns off their hostility they will return to neutral, but the other player will still be hostile to them. This is to prevent players from being able to simply turn off another's declaration of hostility.

Hostile players can target each other, and each other's minions, just as if they were monsters. Hostile players show up on the minimap as red X's, and the level that hostile players are occupying does not display in the party menu.

Death

Dying to another player is somewhat different than dying to a monster. There is no experience penalty upon death on the Nightmare and Hell difficulties, when you die to another player. The gold penalty still exists, and functions just as it does when characters die to monsters.

In addition, characters killed by other characters drop an ear. These squishy objects display the name of the dead character, along with their class and level. It's possible for a single character to drop multiple ears, and yes, they can still hear just fine afterwards. Ears are kept as trophies, or proof of a triumph in battle, and naturally, Hardcore ears are prized much more highly, since that's the only death HC characters get.

Ears can not be used for anything other than keepsakes; they are not valuable to sell and there are not any Horadric Cube recipes that use them, though rumors to that nature pop up from time to time.

PvP Details

Damage is reduced considerably in PvP combat, and attacks and spells will deal just 1/6th their usual damage. Others are tweaked individually:
- The Paladin's Thorns aura deals just 1/10th its usual damage.
- The Necromancer's Iron Maiden curse does 1/4 its listed damage.

The duration of spells is not affected, nor is the duration of cold and poison attacks.

The "hit slows target" modifier is capped at a maximum of 50% slower, in PVP.

Minions attack hostile players or their minions, but their damage is reduced by half.

Most spells with a duration of effect, such as the Sorceress' Firewall and Hydra, the Assassin's traps, the Druid's Volcano, and others, are dispelled when their caster declares hostility on another player. (This was patched in to prevent players from casting these spells on top of other players, then zipping to town and going hostile while the spells were still active.)
- There are some bugs with this as of v1.11; the Sorceress' Blizzard spell turns invisible but continues to deal damage (for the 4 second duration), and the Druid's Fissure spell continues as normal (3.2sec duration), and will deal damage to anyone in the area when hostility is declared.

Players must wait 10 seconds after declaring hostility before they can leave town via a waypoint or town portal.

Some skills do not work on other players at all. Which do not can be determined by reading the skill hover information in the skill tree. If a skill says:
- Enemies, then it will work on players and monsters.
- Monsters, it will only work on monsters. (Spells that change behavior, such as the Paladin's Conversion, fall into this group.)

Avoiding PKs

Most characters who are set up to kill monsters are ill-prepared for a fight against a dueler or a PK. Serious PVP players have their characters loaded up with specialized equipment, their builds optimized to kill other players, and they have a lot of practice taking on people, who have very different strengths and weaknesses than do the mindless hordes of monsters. Most PvE or PvM (Player vs. Environment/Monsters) characters are not interested in dueling PVP characters, and as such PKs range from annoyances in softcore games, to dire menaces in hardcore games. Avoiding such would-be killers is a priority for many players, and there are a few ways to do it.

The easiest way to avoid PKs or duelers is to play in private, password-protected games. Play with friends and only invite people you know or trust to play with you, and you should be untroubled.

If you must create public games, use the level minimum and maximum settings. This won't help against PKs near your level, but it will at least keep any very high level characters from joining in and ruining your fun. You can also limit the maximum number of players, to keep a whole gang from jumping in.

When new players join the game, check their levels and names. If a character looks to be way too high level to play in your area, and asks to join your party, they might be a PK hoping to use the friendly party menu to see what level you are on. Many PKs are less subtle, and will simply ask where you are. Don't tell them, or lie, especially if you're not in a game that gives it away in the name. "BaalRuns," for instance.

A good trick to ditch a PK if you are most of the way through a quest and don't want to simply abandon the game is to exit it, wait a moment, and then rejoin. PKs will usually leave the game once no players remain, and since an established game will stay up for at least 5 minutes after the last player leaves, you can often get back in and resume your play.

Even if the above tricks don't work, you should still be able to stay alive with quick reflexes. If a player declares hostility, it's always possible to get back to town before they can reach you, if you're quick with your town portal. Various patches have added delays after hostility is declared, and unless you are standing right on top of a waypoint, you'll never be caught before you can run to the safety of town.

PvP Standards

Dueling in Diablo II is not controlled by the game rules, but there are many informal and unwritten rules amongst players. Some items are bugged and too powerful, or are considered cheap and their use is not permitted in fair duels. Some tactics are frowned upon, and in many duels drinking potions is not allowed. Other duels are limited by character level, and low-level duels are popular since they limit the potential equipment and skills that can be used. When joining a dueling game, you may wish to take a moment to establish what the rules are, lest you transgress, or go forth unprepared for what you are about to face.

Hardcore

In hardcore duels, anything goes since the stakes are so high. Expect to see players use potions of all types, shrines, any possible equipment set up, etc. Beware anyone who promises a fair, one on one fight; they might have friends in the game waiting their moment to join in. This goes for softcore duels as well, but there you've only got an ear to lose, and if someone has to cheat to win, you can take that as a compliment and leave with your head held high.

Softcore

In softcore dueling there is more variety and sportsmanship, since it's more of an exhibition sport.

Most duelers consider it poor form to drink red or purple potions during a duel. Blue potions are allowed, but generally not for sorceresses using Energy Shield.

In v1.11 virtually all equipment is allowed, since most of the large bugs and exploits with equipment were ironed out in earlier patches. One touchy issue is the use of high amounts of damage absorption, usually obtained by socketing armor/helms/shields with Sol runes. Enough of this property, referred to as "sorb," can make a character virtually to physical immune in PVP, thanks to the damage penalties built into PVP in Diablo II. Elemental attackers make similar complaints about equipment that gives extremely high resistance and absorption to a given element, but this is more of a rock/paper/scissors type issue, since while a character can become almost immune to one element, they'll be very vulnerable to others.

When it comes to tactics in dueling, it's considered bad manners to play too defensively or cautiously. Characters with tremendous foot speed or the ability to teleport can play keep-away indefinitely, and if they have a skill (such as Holy Fire or Thunder Storm), that deals constant damage to any target in the very large radius of effect, their victory is almost assured. This is technically legal, but is considered very cheap and will result in other players simply declining to duel against you.

Dueling isn't just about winning; it's about having fun in a contest that could go either way. Using a technique or equipment setup that guarantees you victory isn't much fun, since there's no skill or challenge in the game. As new tricks and exploits are discovered, players need to make some compromises if they want to keep dueling fun and viable, and this means sometimes not using certain overpowered builds or items.