Any good ways to counter harm?

[Elaer]

If you really want to twink out...

Some nasty options might come from combining various supplements...

If you have a 17th level Wizard, and use Tome & Blood, then Hide Life takes the bite out off both Harm and Fighters (and just about everything except disintegrate or subdual damage).

Monstrous Regeneration (MoF?) as a persistant spell, along with immunity to Fire and Acid (Energy Immunity? Protection From Elements?)

Anti-Magic Aura on creatures that can go toe-to-toe with a debuffed fighter...

These are just off the top of my head

 

[Nareau]

Some tactics for Imix

Use Maliskra (the medusa) to good effect. She's actually only a 5th level cleric (with another level in a PrC).
Imix's touch AC is 16. Protection from Good will boost it to 18 (vs. the good guys).
If you feel like changing around the equipment list for Maliskra, give her a couple of potions of Haste. That'll push his touch AC to 22.
Have her prep a couple of Summon Monster spells in the hopes the PC's will burn some spells on them.
I would certainly have her prep a couple of Protection From Elements (Cold). The PC's know their fighting fire-types, so they'll be preparing Cold spells.
Also remember that clerics tend to have low Ref saves. So I would start out with Imix and Maliskra summoning some nasties, then hitting the party with Fireball and Fire Seeds. The PC's will no doubt have a lot of Protection From Fire spells cast on them, so you should wear them down one at a time.
You should also have Maliskra try and hit the party sorceror or rogue with her Petrifying Gaze.
You could also have her cast Shield Other on Imix, and hide in the background healing herself.

Keep in mind that single opponents will fall easily to organized parties. It's vital that Imix have some allies (summoned creatures) to keep the PC's busy. I would target their spellcasters first, then work up to the fighter types. That way, you're much more likely to even the playing field early in the battle.

Incidentally, are you really firmly opposed to house-ruling Harm? You might want to think about that carefully (if you haven't already). You're right to worry--it can ruin what would otherwise be a very cool and epic battle.

 

[hong]

Just nerf harm. Everyone else does it, there's no shame.

 

[Lord Ben]

Well, we've been using harm as is for several months now, I don't want to change right at the end. I think in all that time it's only been used once and that was by Hedrack against a PC. The PC never takes it because he knows it's overpowered and he has other 6th level spells he likes better.

If I did house rule it, then it would be similiar to the power word stun rules or something. It would only affect creatures in a certain HP range or perhaps no higher hp then the cleric.

 

[Rowenstin]

Imix has reach, so use the AoO the cleric provokes in his way to touch it not to bash him but to make a trip attack. Since he´s so big and strong it´s very likely that the cleric will kiss the dust. Bash him the following roudn with that colosal sword.