The last level of this great game. I hope you've had fun. I'm going to sparsely talk about this level because I don't want to spoil the end for those who are looking ahead or those who haven't beaten the game (which should be everyone reading this...). To beat this level, you'll need to hit the switches in the correct order. Use teleports as they appear. The switches all activate different telports. The teleports aren't listed because they would confuse more than help (most only appear if the correct switches are hit). You may notice that the Xanathar key isn't on this level, and it isn't.
To beat this level, you have to actually go back to level 5 again (Hint: A teleport is activated by the last switch that creates a teleport that will take you there). The Xanathar key is in a "Secret Area," an area you reach by entering... guess what? A teleport.
The enemies in this level should be no problem to your characters. The boss at the end of this game is supposed to be very tough. (If you can't guess what it's going to be, look at the title of this game) A skilled party should be able to beat it handily. You can use a variety of strategies, charge at it with warriors and back them up with your ranged characters, or fireball (insert favorite spell first) them first. Have fun beating the game! I hope the Walkthrough helped.