Well, in my experience, the Fireshield trick has been absolutely
worthless against Kuroisan. A brief recap of my 2 duels with the bastard:
Tactics Run #1: My first game as a Cavalier. Did the Improved Guarded Compound very late in the game, with the result that Kuroisan showed up in Suldenessallar. Nalia and Imoen bounced him back and forth between their PfMWs and Breaches until he was vulnerable, then the rest of us charged in. Once we knew his pattern, he was toast.
Tactics Run #2: My first game as a Wild Mage. Did the Improved Guarded Compound very early (there's a reason why I say Tactics should be called the "Invisibility Potions MOD"), so Kuroisan hit us at a very low level--trying to fight him with only 2 or 3 PfMW slots is
not for the faint of heart. So I had no qualms with using cheese against him, and tried the Fireshield method. Imagine my surprise when I discovered that not only is Kuroisan
immune to Fire and Cold damage, but also has
non-Breachable Fireshield Red and Blue. Yes, these effects were verified during subsequent tests.
- Using a Fireshield (without first casting PfFire and PfCold) = You get fried/toasted on his Fireshields, while he's Immune to your damage.
- Using a Fireshield without PfFire and PfCold, but you cast Breach on him first = Exact same result.
- You use PfAcid, PfFire, and PfCold, then use the Fireshield = The game lags while you both take thousands of hits that do 0 damage. Meanwhile, he's eating through your Stoneskins, lowering your Acid resistance, and the constant barrage of hits means you can't refresh your PfMW.
Easiest way (especially for a Solo Blade):
1) Protection from Acid.
2) Oil of Speed.
3) Breach.
4) Invisibility Potion.
5) Run to a safe distance.
6) Go back to Step 3.