After a defeat that ended in Kolaar's forces losing control of a port city, he was able to salvage his forces and take them into the Underdark. By inspiring revolt in the drow slaves coupled with strategic attacks, Kolaar's forces have seized a drow city. In the last adventure, the players met a human wizard outside the city who claimed to have studied here and wishes for this threat to be gone. With his help, they gain the alliance of some previously-captive dwarven spirits who go and kill Oal.
Now defenseless except for his tactical mind and fighting prowess, the players can move directly against Kolaar. I am sure you can see that I want this confrontation to be epic and interesting.
Here's the problem. One of the players is a psionicist. A psionicist who likes to use the psionic equivalent of Disintegrate. Were he a spellcaster, I would have Kolaar use tactics like a stone with Silence on it (much like drow have Darkness cast on stones wrapped in clay) to help disrupt or hinder the player's spellcasting. But as far as I can tell there is nothing short of stunning or knocking the player out that can disrupt psionics. And even then, this feels wrong, because I don't want the player to not be able to do anything. But if I let him do something, he's going to sever the boss' spinal cord or teleport its brain to Nebraska.
Any ideas? I don't want to just say things like, "Oh, well, your ability doesn't work for some reason." That seems cheap.
