From Diablo Wiki
Warnings are intended to keep players safe from hacks, rips offs, con artists, and even the occasional in-game danger. This section serves the same purpose as consumer information services and TV shows like Fight Back. Knowledge is power, and knowing what to watch out for and how the game actually works will keep you from running afoul of an unfortunate fate.
This page contains general purpose warnings, and some links to other pages in this section. See the Warnings Category for a full list of articles on this issue. Be sure you also check out the hacks, few of which involve actual hacking and most of which rely heavily on social engineering to work their black magic.
Open Battle.net Precautions
Whether you're playing Diablo I or Diablo II, always back up your characters (MP chars in D1, open chars in D2) before taking them online, since there are hacks galore in the unregulated world of open Battle.net. You can be killed in town, your corpse popped, or worse, and if you haven't backed up your character recently, you are out of luck and in a world of hurt. For example:
- "Yesterday I was online in open Battle.net and someone offered to trade me a Wormskull and ring of Jordan for some unique armor and a unique ring (that I found myself). I did it and then noticed that the Wormskull was glitching and was in the corner of the inventory screen. Once I left the game to try and fix it and tried to go into another room it said, BAD ITEM. So I just exited Battle.net and went to single player to look at my new items when my character was suddenly COMPLETELY ERASED except for the fact that he was still Sir (meaning I was in nightmare) and he had finished all the quests. Everything else was gone and he was restarted as a level 1 Necro. -- Mike
Backing up your characters is very easy in D2. In your Diablo II folder there is a folder called "save". In this you'll see files with your character names. The ones with .d2s extension are your character save files, you just need to copy those to another folder, and you can then restore them at any time by copying that file back to the /save folder. Be sure you don't overwrite a more recent version of your character by accident, and make frequent back ups so you don't lose play time or items if you have to restore.
More tips on backing up, muling items, and other single player issues can be seen in our Single Player FAQ.
Monsters to Watch Out For
Most of the warnings here are to watch out for other players, but let's not forget that the actual game can be dangerous as well. Most players find out about what to watch for the hard way. In general, normal monsters are almost never dangerous in D2. You can get swarmed by Cows or others, but generally speaking it's boss monsters that you have to watch out for.
Prior to v1.10 nerfing their bolts, the most dangerous monster type for most players is an MSLE (Multi-shot Lightning-Enchanted) boss. The number of bolts these monsters emit when you hit them are multiplied by their MultiShot mod. LE stacks with many other types of modifier, such as Cold, Fire, Extra Strong, and more. The most dangerous possible is an MSLE with Conviction, since this lowers your resistances. In v1.09 and earlier, most characters, even those with maximum lightning resistance, would die almost instantly to the bolts from an MSLE while they were afflicted by Conviction on. Other dangerous bosses are FECE, especially with other mods stacking. The Cold Nova self destruct will carry damage from other mods, and if you get one with Fire, or Extra Strong, or Conviction, it can really hurt. Damage upwards of 1000 has been reported, even by players with good resistances.
Learn what the various Auras do and look like. It's important that you be able to recognize if monsters have Fanaticism, or Conviction, or Might, and know what other mods will be dangerous when modified by those Auras. Early in D2X Holy Shock was a terror, often dealing 800 or more damage in Nightmare, and 1500 or more in Hell. Numerous HC characters died in one hit from an otherwise wimpy Holy Shock boss. Blizzard appears to have toned this down in v1.08 and later, since we've not heard or seen any one hit deaths to Holy Shock since then. Might is especially dangerous since it will share, and on Hell the radius of sharing is enormous. You can have every monster on a level with Might, and be two or three screens from the actual Might Aura boss. Might can increase monster damage 3 or 4x in Hell, and if you are Cursed also you can double their damage. If they are Extra Strong, you can be looking at thousands of damage in one hit.
Monsters that are most dangerous when hitting you have Fanaticism, Might, Extra Strong, Cursed, Extra Fast, and Holy Shock. Extra Fast monsters with Fanaticism can hit so fast that you will be stun locked and unable to fight back or flee.