Stuck...put the poison from the wyvern tails in 4 pools...door still wont open what do i do now?

The door won't open until Thorasskus (is that the right name?) that head snakey guy is dead.

Usually he escapes, and you have to go hunt him down elsewhere on the level.

SPOILER


The kid in the room with all the Efreties is the level boss. If one of your charecters cant expose him then go back and talk to your fake Histashchi friend. He will tell you the truth.

The High Priest (which is what the boy really is) will go to the room with 5 doors when he gets hurt. So you will have to go hunt him there, before you can get to the next level.

When I played, the bridge went up and Thorasskus was invisible. I went through the tunnel to the treasure room, rested and went back. I found Thorasskus there, and he had summoned an iron golem. I beat him in his room. Maybe just depends on some random factors.