Go across the bridge made of chain links. Go straight through the door on the other side. Walk through the tunnel until you reach another door. Walk through it. Next walk up to the four fire enemies. You can try to sneak pass them, fight them, or have one person get into a battle and someone else to sneak bye. The person who made a battle then flees and ports to the person who snuck bye. Next repeat on the three myth people. Walk to the left and go to the chains leading up into the air. This is the volcano elevator. Press X and go through. Next fight the fire gurtok, then the ice gurtok. Have someone stand at the crystal stands on either side of the gurtoks and wait. Someone go through the door on the FIRE GURTOK's side and follow the tunnel. Then everyone activate the crystal stands near the gurtoks and at the end of the tunnel. After that go through the door between the gurtoks and into Malistaires lair. Next follow the hallway and defeat the two draconians at the same time. Once that is done go into the room with Malistaire and fight the four death enemies. After a short cut scene (I recommend lots of pictures.) you can fight Malistaire.
*Note: If one of your friends cannot port because it is full, have them go into the dungeon and then port.
Quinn Dragonwhisper-Grandmaster Myth Benjamin Dragonblade-Grandmaster Storm
You will need at least two wizards to activate the crystal stands. :)
One wizard marks the location at the first crystal stand and runs to the second crystal stand (the two closest to the Gurtuks would be the easiest), while the second wizard is ready to activiate the third crystal stand. The first wizard activates the second crystal, then ports to the first to activate it, while the second wizard activates the third. This will unlock the door. :)
Sorry, I know of no way for only one wizard to activate all three at the same time. :(
I hope what I wrote does make sense. I have already done it twice this way and it works. :)