Witchaven II: Blood Vengeance/Level 10: Straits of Perdition

Once again, you start off under attack. Fight your way through and head north, being wary of the lava cracks. Where the northern wall nips in, you'll find a pull chain that opens the tower where the brass key is. Jump to safely get the key, or use fire resistance if you've got enough to spare. Once you've got it, head west through the brass key door.

Pull the chain in the next room to open a big outdoor area, and continue through into a large chamber full of barrels. To the north and south are side areas, and the north one, if you visit it, is a trap from this approach, so go upstairs through the door to the west.

Through the eleven o'clock door from the pentagram room, open the secret door at the end of the short passage. You'll find a sort of big lava arena beyond. Pull the chain down there to make the pentagram accessible.

The room you find beyond the eight o'clock door will lead you to the glass key; once you've got it, the seven o'clock door can be opened. Don't be fooled by the simplicity of this room with the floor plate; explore the edge of the structure to find a ramp down to the black key.

Through the one o'clock door you'll find a rather oddball mechanism: a floor pad that requires the black key you just got. Trigger it and a great creaking will indicate the opening of the doors that barred the end of the ten o'clock passage; pass this way to return the pentagram to its place and continue your quest.

Tips and secrets:
 * Go to the end of the hallway that runs south of the big outdoor area and break through the stained glass to find a weapon enchantment well.
 * To the south of the aforementioned hallway is a treasure room, also hidden by stained glass.
 * Through the five o'clock door from the pentagram room, find an Onyx Ring and a Fly spell (which you need to get back out of the lava pit there.)
 * In the big lava arena where you pulled the chain for the pentagram, fly north to the potions on the ledges. From there, you can fly down into a treasure room with gold and an ankh further north (this is the area that would trap you in if you went there via the hall from the barrel room).