Tips

General Tips
Save Often
Take out Enemies One at a Time
Collect Fire Weapons
How To Defeat...
Trolls
Mages
Dragons
Irenicus

General Tips

Save Often
Not only should you save your game after every battle or major dialogue, I also recommend keeping several saved game files for each of your games. This will allow to backtrack several saves if you, for instance, find yourself in an area that is too dificult. I usually have one save game from the beginning of the current chapter, one save game from the beginning of the current area I'm working on, and then one or more in the current area. I often make temporary saves if I want to experiment somewhere but don't want my experiments as part of my main game.

Take out enemies one at a time
A strategy I use for nearly all difficult battles I encounter is to take out the enemies one at a time. As you approach the area where the enemies are, take one step at a time. When a single enemy appears, stop and retreat a little ways. As the enemy approaches, have all your archers fire at it. If it isn't dead by the time it reaches your front character, your front row fighters can finish it off pretty quickly. Once the enemy is dead, take another step forward until the next enemy appears. This way you will take out each of the enemies in the group six-on-one instead of being outnumbered. You can even save between enemies.

This strategy does not always work. Sometimes when a single enemy sees you and starts attacking, all the other enemies in the group will move toward you as well, even if they are not visible on the screen. Sometimes if you retreat far enough, however, you will be able to separate the enemies and attack them individually.

Collect Fire Weapons
Some enemies in the game can only be killed by fire or acid, so it is a good idea to keep any fire weapons that you find and equip them to finish off these enemies.

How to Defeat...

Trolls
Trolls can only be defeated by fire or acid. Attack the troll until it falls over unconsious and then finish it off with a fire spell or weapon. I suggest using mostly fire melee weapons or fire arrows and save your spells for other enemies since trolls do not attack your party when they are unconsious and you have a fair bit of time to finish him off before he wakes up.

Mages
Mages can range from very weak to very powerful. For very weak mages, such as Orc Shamans and Kobold Witch Doctors, I usually don't give them any special attention and just kill them when I reach them. For mages that are a little more difficult, it is often sufficient to defeat them first in a battle before they can cast too many spells and then defeat the other non-mages in the battle.

Some mages will cast protection spells such as Mirror Image, Stoneskin, and Fireshield. Cast Breach, Remove Magic, Pierce Magic, or Pierce Shield on these enemies first to remove these protections and you will then be able to attack them normally.

The most powerful mages will protect themselves with Protection from Magic Weapons, Mantle, Absolute Immunity, Globe of Invulnerability, and Spell Trap spells. Since most of these spells can not be dispelled, you have to way for them to ware off on their own. Run away from the enemy so that they are not on the screen and are not following you. Wait a minute or two for the spell(s) to ware off and return to attack them. Although this is somewhat cheap, it is very effective.

Dragons
Anyone who has Stoneskin, Mirror Image, Globe of Invulnerability, and similar spells, should cast these before the battle. Also take lots of
Potions of Extra Healing with you into battle. Have your fighters drink Potions of Strength (preferable Cloud Giant or Storm Giant) to improve their THACO and damage. Make sure you save your game before you fight, because you probably won't win on your first try. If you are going to fight Firkraag, cast Protection from Fire on every one of your characters and you will be completely invulnerable to his fire breath attack. Even if you are fighting some other dragon, you may wish to cast Protection from Fire on all your characters anyway, so that you can throw fireballs at the dragon and not have to worry about hurting your own party.

The first spell most of the dragons cast is Stoneskin, so have all of your mages who know Breach, Pierce Magic, or Pierce Shield, cast them to remove this protection and lower the dragon's magic resistance. Once his stoneskin is gone, attack him with everything you've got. If a party member is getting hurt, move them behind someone with a Stoneskin spell so that the dragon attacks that person instead. You may also want to cast some Summon Monster spells to draw his attacks and prevent your party members from receiving damage. Dragons have strong Magic Resistance, but many attack spells can still get through. I found Magic Missile particularly useful because it is very fast, your mages can cast a lot of them, and every spell sends several missiles so he may be resistant to some of them, but probably not all of them.

Finally, have patience. Dragons are very difficult enemies and you may have to fight them several times before you defeat them.

Irenicus
Irenicus is a very powerful mage. When you fight him in the Tree of Life in Suldanessellar, he will cast Absolute Immunity, which makes him invulnerable to all physical attacks, and Spell Trap, which makes him invulnerable to all magical attacks. This certainly doesn't seem very fair! As soon as the battle begins, have your best mage cast Globe of Invulnerability, Spell Trap, and any other magic protection spells they have. Have the other five members of your party retreat from the battle to the other side of the area as fast as you can. Irenicus will cast his attack spells at the mage you left behind, but since he cast Time Stop, none of his spells will take effect until time resumes, so he will cast many spells at the same person, even if his first death spell kills the mage. Do not worry if your mage or any other of your characters die in this battle, because they will automatically be ressurected for the next area. Your mage has to survive long enough for Irenicus to cast his second Absolute Immunity spell, however. If your mage survives, keep running away from Irenicus until his Absolute Immunity spell wares off, otherwise, just wait for a few minutes and then attack him. Although he is magically very powerful, he is very weak physically, and without his Absolute Immunity protection, he will die fairly quickly.

You will have to fight Irenicus once more at the end of the Nine Hells area. Although his magic is not as powerful as the first time you fought him, he will become the Slayer and will have four demons join him in battle. Both times I fought this battle, Irenicus became the Slayer, cast a few protection spells, and then teleported away from the battle so that I was able to defeat the four demons first without any harasment. Afterwards, I was able to heal my party members before searching for him and attacking him. Since the area is much smaller than the one where you fought Irenicus previously, you may not be able to get him off the screen so that you can wait in peace for his spell protections to ware off. Just fight him with everything you've got and don't worry if any of your party members die, because Queen Ellesime will ressurect them all after the battle.