A directive composed by site owner Dei (Diablo Stronghold) containing common knowledge never publicly shared (presumably) until now (10/13/2017)

Introduction
To start things off right, firstly what will be explained is what to expect during a duel, or a tournament, what have you.. The mechanics of Diablo 1 PvP will follow below this preface. Gear will not be covered here since item setups are objective and most of the required gear guidelines available elsewhere usually demand OTT high-end gear not readily accessible to the average player; so we will focus on the most important information to become familiarized with. *Disclaimer* What follows is in no way a complete or extensive guide to Diablo 1 PvP or its mechanics therein. Styles of PvP vary, but in general I speak of the "Northern Playstyle" explained below.
Northern House-Rules & Practice (Common Knowledge)
-8 potions allowed per duel (one full belt) - [side note]: it is wisest to use full rejuvenation potions

-One opponent must cast the spell 'Guardian' before a duel; and only until the spell dissipates/concludes may the duel begin

-The act of re-equipping items or equipping a new item during a duel is frowned upon because it is known to cause considerable lag (mostly this concerns weapon-swapping during a match, due to a glitch whilst attacking this will cause insta-death for the opponent)

-During a melee vs. melee duel, non-static combat is encouraged. (e.g. swinging opposite ways once in a while to produce & allow intervals of escape, movement, action and/or correction of desync [or async] - a commendable strategy.. An example of correcting desync during a melee vs. melee duel would simply be described as re-engaging your opponent (I.E. pause combat and walk a tile away from your opponent then back again, then resume combat; or, teleport away and teleport/walk back)

-Any abuse of the 'mana no-stun bug' is an obvious no-no / Including 'Zen Setup' sorcerers (I.E. using balance, stability & harmony) in conjunction with one another, which is comparable to the 'mana no stun-bug' (Especially if zen is used with 100% fast block) - due to the nature of the effect of both of these 'bugs', this basically enables a sorcerer to practically cast spells through stunlock. Though zen is not as bad of a bug, it's still discouraged. You can find an example of this being tested here: https://youtu.be/nRUVGds2nNY

*note* The use of the 'torch' hack/mod is known to cause major desync/async issues and even player lag, it is noticeably destructive

Needless to say.. Any use of any exploit, cheat, mod and/or bug etc is a blatant low-blow to your opponent & is considered cheating.
Lag / Desync:
In the event of a duel, all players should have little to no expectations for the outcome and results of a single match. This surely raises questions, but here is the answer: you can believe skill definitely takes part in any duel but above all else (at most 85%) Desync & Lag is the major factor. You can be a great Warrior duelist and still lose to a newb Rogue or Sorceror due to delayed damage (caused by high latency/combined lag between all players in a single game) - examples of this can be seen in multiple Diablo 1 PvP videos on YouTube where you would see damage virtually come from out of nowhere.

The other factor is Desync. It ties into Latency/Lag and is the term used to describe what one is seeing on his or her screen while on the opponent's screen is shown something entirely different, or in some cases the total opposite.. Usually, this is a server-side problem (and arguably a problem with Diablo's netcode), not client-side, even though better internet connections exist today.

Sadly, there is no way around it other than adapting to how lag works within Diablo and learning to utilize techniques and strategies that can (in some cases) insure survival and/or a victory. One of these strategies is to be as unpredictable as possible in any duel you might partake in. For example, a Bow Rogue should always stay mobile during any duel to capitalize on their damage output and survivability. If you stay still long enough (even 2-3 seconds or less) you give opening to the opponent and in some instances this can cost you the entire duel. Occasionally, you will just flat-out not see the attack or any character animation at all when dueling another player! This is called Character/Player Lag. Avoiding this is nearly impossible, so staying mobile at all times is very effective when it comes to initializing a defense to problems such as this.

As for Warrior, your worries are much slimmer to some extent. The only problems for a Warrior should be an elemental-bow wielding Rogue or a Sorcerer with splvl20.. Or in some cases, a Warrior might have to face an extremely high AC tank/battle mage or High AC Rogue; in which case this would force the Warrior to equip gold/perfection jewelry which will drastically decrease the Warrior's resources. A Warrior should come out ontop though, if cunning & strategy is properly drawn out 'till the end. In all, Lag/Desync should be the main worry here for all classes regardless of the specific matchup.
*SIDE NOTE* very important - always hold Shift while attacking using Left Click (with a Melee Character) to block arrows
Tournament-Play:
Usually a tournament will consist of some form of bracket which is a tree-diagram producing the series of duels played during a knockout competition. The type of bracket used most commonly is that of the single-elimination tournament; usually divided between two groups, Example: Group A / Group B which would primarily have the same amount of participants. The way it would work would be: Group A (player1) vs. Group A (player2) - determining who has won most out of the amount of rounds (usually 4 rounds per encounter) the winner would move on to the next competitor in their respective group-bracket. This will continue until 2-4 finalists remain in both groups respectively. At that point they will all face eachother in the semi-finals & third-place playoffs until the last 2 finalists remain in which they would have their final match which would determine the winner of the tournament. In other cases, say, an FFA tournament; a 1st place winner would be determined by points/total kills alone.
PvP Basics (Melee Focus):
It is imperative for Melee builds to utilize diagonal walk (in moderation) when facing a ranged-attacker. Doing this will help prevent incoming damage, but not always, because of problems like desync. In most occurrences diagonal walk is primarily used to avoid oncoming bombardment and to provide momentary intervals for a preemptive strike or a well-timed escape. Below is an example of how 'walking the line' should be executed.
It should also be made aware that certain angles of maneuvered elemental-bow attacks can prove lethal.. One should not only know of the 'bugged' trapped chests in the dungeons below the cathedral, but also of the 'bugged' arrows similarly experienced during a duel versus a bow rogue. Explained below in this example you will see a bow rogue successfully achieving a 'bugged' arrow strike.
PvP Basics (Ranged Focus):
Like Melee class builds, it is imperative for Ranged class builds to always be aware of their surroundings and to also use those surroundings to their advantage. Yet again, in some cases, obstacles like the pillars on Dlvl1-4 or the skull lever cage on Dlvl16 where you will duel can work against you due to desync. On your side of the screen you may be one tile under an obstacle, while on the opponent's screen you are right next to them 2 tiles upward on the opposite end. Mobility is the next key thing here, as mentioned before, staying still can cost you the entire duel. You have to be cautious, as ranged classes may have the highest DPS output in the game they can still be brought down by a few swings of a Warrior's sword or a Sorcerer's lethal Fireball spell. Below is an image of an example of how a Ranged Class can use such an obstacle to their advantage:
PvP Actions & Maneuvers (Melee)
From a Melee Focus, especially in an encounter versus a Ranged Class, it's always most suitable to stay in motion. We call this 'Diagonal Walk' or 'Diawalk' for short. What this allows a Melee Class to do during a duel vs. a Ranged Class, is to strongly hold a defense that will in most cases dodge any incoming projectile attack (like arrows, Fireball, etc) while 'walking the line'. It is also good to hold down Shift while in diagonal walk vs. a bow rogue in case desync may arise; this should help blocking of offscreen hits.

Another form of staying in motion (though not all duelists have the luxury to do so, due to lack of mana) is to utilize 'Teleport' and 'Phasing'. Doing this allows a Melee Class to dominate the arena while camouflaging oneself from a ranged opponent (this wouldn't be much use vs. another melee opponent unless they are fixated on using many offensive spells).. If timed correctly, and with precision, this can insure both survivability and perfect tele-kills.
Below are some common PvP Techniques which are primarily used by Melee Classes:
Tele-Kill (Teleport-Kill)
Tele-Delay (Teleport-Delay)
Double-Flash
 
This maneuver is widely common even among players that are unfamiliar with PvP.
This maneuver isn't very well known, but to some it's a tactic used as well with Tele-Kill (Teleport-Kill)
  The use of Double-Flash is undoubtedly one of the most lethal attacks in PvP regardless of which class uses the maneuver
 
To carry out such a move is pretty simple once you get the hang of it. All you need to do is use your cursor in-game to select a player then use the 'Teleport' spell; bringing your character directly ontop of the opponent. In conjunction with that, with the delay of the Teleport resolving, also use Left Click to begin attacking once you land. In short, you highlight your opponent, Right Click (Teleport) directly to them, and before your Teleport even begins to resolve, also Left Click the same highlighted opponent to immediately engage in combat. Hence, Tele-Kill, because this is an unexpected attack that can sometimes kill an opponent before they can even react. Here is an example of this in action: Click Here
 To carry out this technique is a bit difficult to explain. I believe both lag and desync most likely tie into how this actually works. Performing the action is similar to Tele-Kill, as such (Example): you highlight the opponent with your cursor, timed correctly when the opponent begins to teleport away, simultaneously use Right Click to Teleport to them in a delayed attack. In some cases you get to the same exact spot as the opponent teleported to. In other cases you might have been a fraction of time off or only got a single strike through..But, depending on the lag, you can still 'strike their shadow' (I.E. holding shift while attacking the same spot the enemy was in when you first engaged them in combat.) This move can also bring the opponent back from a half-resolved Teleport escape. Here is an example of this in action: Click Here
This one is very easy to explain.. Let's say you were in a melee vs. melee duel and you decide to use this spell. *Note* the most effective way to use 'Flash' is to be directly above your opponent. In these instances, the one receiving damage from 'Flash' will really feel the pain :-) otherwise if you plan on using this spell while below your opponent the damage will be miniscule in comparison. So just adding two and two together: Right Clicking double fast to have your character cast the spell twice will enforce the damage to be even double or more than normally expected. This is fair-game in most occurances, since it's a widely known and commonly used attack even in PvM gameplay. Use at your own risk though, since carrying out any spell decreases your block to 0%, basically threatening the simple action of even attempting to cast the spell while in a melee duel. Here is an example of this in action: Click Here
PvP Actions & Maneuvers (Ranged)
Just like the Melee Focus, an encounter versus a Melee Class while using a Ranged Class it is always most suitable to stay in motion. Except one main important factor to point out: diagonal walk is absolutely not an option here since this gives the Melee combatant opportunity to easily strike and/or kill you in one clean swoop. You should be utilizing both the spells 'Phasing' & 'Teleport' for your main source of movement. These spells are also your main source for strategic attacks and maneuvers that could insure your victory in a duel, but occasionally these same maneuvers can also bring you to your doom depending on the circumstance(s).

It must be said though, in case you are a Ranged Class facing a Ranged-Capable opponent (like a spell heavy bow rogue or another sorcerer) diagonal walk is still a promising strategy only if time and luck is on your side. If a sorcerer is dueling another sorcerer capable of melee attacks while retaining a spell level of 18, diagonal walk would not be the first choice of tactical defense. Stay keen with your maneuvers and techniques, especially when facing an opponent who uses an uncommon build or who's style varies.
Below are some common PvP Techniques which are primarily used by Ranged Classes:
Tele AA (Teleport Auto-Aim)
 Phasing AA (Phasing Auto-Aim)
 Counter-Casting
Tele-Aim is the best choice attack to go with for either sorc or bow rogue. It just equally demands skill as it does with any other attack you may carry out.
This move is suggested for adepts to the sheer speed limits of ranged attacks. This form of AA is not common, but I argue it to be the best; especially for sorcerer.
As long as there's an opening, might as well go for the jugular. Unless you are unable to, this maneuver proves to be undeniably tactical.
To carry out such an attack takes time and patience, because it involves the partnered usage of 'Teleport' along with projectile attacks. It can best be described as the opposite of 'Tele-Kill', whereas this attack promotes ranged auto-targeting in comparison to close-range targeting. *Note* in general, it is always suggested to have 'swords crossed', but especially if you are a bow rogue; because both Right Click & Left Click are used in conjunction with one another to properly perform the technique. (Example): while you are at a distance to an opponent, with 'Teleport' currently selected as your primary spell, cast the spell at a chosen location while the opponent still appears within view. Before your Teleport fully resolves; (meaning, before you land at the chosen destination); highlight your opponent with the cursor and then Left Click (if using a bow) or Right Click (if using spells). If done properly, you will have fired a successful shot upon landing; regardless of the position your opponent may have been in prior to your Teleport. Hence, 'Auto-Aim'. Here is an example of this in action: Click Here
When it comes to Phase-Aim, it is practically the same thing as Tele-Aim minus the fact you do not have a choice where you land. To some, this is extremely difficult to pull off when compared to Tele-Aim, but I will do my best to explain how you are supposed to auto-aim with the spell 'Phasing'. *Note* assuming you have 'Teleport' + 'Phasing' + 'Fireball' hotkeyed on keys F5-F8 (if you are a sorcerer or an adventurous rogue) it is worthy to keep in mind that you will be switching between these spells very frequently and at speeds that take precision and focus if you are planning to pull off such a maneuver. In the end, it basically comes down to instinct and reflexes when using Right Click in conjunction with fast-switching of spells. (Example): Just like with Tele-Aim, when you are at a distance to an opponent, with 'Phasing' currently selected as your primary spell, cast the spell. Before the spell resolves, highlight your opponent with the cursor and promptly switch your primary spell to 'Fireball' and Right Click before landing. While on rogue, the same applies, except replace the Right Click with a Left Click. Done properly, you will have fired a successful shot on your opponent regardless of where you or they are positioned after landing/after Phasing resolves. Here is an example of this in action: Click Here
To carry out a counter-attack using a sorcerer or a spell heavy rogue or warrior, you use openings to your advantage when you are lucky enough to find them. *Note* if on sorcerer or melee rogue, it is recommended to use fast block and attain 100% block so these counter-casts are most effective. If you don't have perfect block, this technique will prove to be very difficult to achieve. (Example): You are on 'diagonal walk' as a sorcerer and your opponent is a bow rogue putting lots of pressure on you with their projectile attacks.. At the right intervals, and if the right opportunity arises, you can step one or more tiles to either the left or to the right and quickly cast 'Fireball' onto your opponent in those few mileseconds it takes for the projectiles to reallign to its target (you). With success, you may be lucky to get a single shot off or two. With that said, this requires some practice, especially if you are incapable or choose not to use perfect block/fast block. Here is an example of this in action: Click Here
In terms of Auto-Aim, the best way to go about it is with ease & moderation. The more spells you spam, especially 'Phasing', you will increase the chances of lag picking up over time..Which in turn will yield bad results on either end, yours or your opponent's screen. It should also be said that just because it is called 'Auto-Aim' it does not automatically mean each attack you successfully fire will hit your target every time. If you're facing a well practiced duelist, you'll either run into problems such as 'Diawalk' and/or camouflage distancing techniques such as their own use of 'Phasing' or 'Teleport' to force you to lose track of them.

Perhaps at another time this page will have more content added to it, since in whole this isn't really a complete compendium to any degree. Hopefully we will see something extensive in time, whether the content is hosted here or otherwise. I hope this information will reach the people who are interested, and I hope it will help you on your glorious path to Diablo 1 PvP.

Cheers & Good luck to every PvP enthusiast out there,
-Dei

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