I know, I know, I play on SCS Insane with everything turned on, so I only have myself to blame, but...How do you normally deal with thieves who seem to have infinite supply of potions of invisibility and infinite backstabbing multiplier? A notable encounter is the improved Chapter 5 final battle, where you have to fight a group of 8 enemies or so, 2 strong mages, at least 2 backstabbing thieves, a priest, 2 fighters and a shapeshifter. I haven't been able to find a way to beat this other than, climbing down the stairs and dealing with groups of 3 or 4 of them at a time. If I go full frontal on them, half of my party gets gibbed.
The problem isn't so much in mages (well, being slowed and confused doesn't help either, but I can deal with them), but in the thieves. Each of them gulps a potion of invisibility every round, backstabs for gazillion damage, and then repeat the same process. I have True Seeing on my druid, but that actually isn't of much help because, from what I understand, True Sight/Seeing is basically an equivalent of Detect Illusion once per round for one turn. So, you reveal the invisible creatures once per round. If they take a potion of invisibility after that, you cannot see them until True Seeing triggers in the next round, which gives them six seconds to do backstab. Invisibility Purge is utterly useless, as it has a casting time of 8, which means I only get to see them at the end of the round and have around 0.5 second to kill them before they go invisible again in the next round. Detect Invisibility/Illusion are faster, but still they take a few seconds - perfectly enough time for their thief to perform the backstab. The only way I can see to reliably deal with them is to turn on True Seeing on a druid, do Invisibility purge with him once per round and do Detect Illusion on the mage. But this is devoting two characters just for detecting the invisible thieves, so the other 6 enemies can tear me another one.
So, general question - how do you usually deal with backstabbing theives?
i should say that my party is CHARNAME (avenger), Kivan (Archer), Ajantis (Undead Hunter), Alora (Assasin), Yeslick (still fighter/cleric) and Xan (Illusionist). I obviously used NPC Customisation part of SCS to assign kits to the NPCs when they join me...