Uniting the Worlds

After you have defeated Alamar, the Dragon Pharaoh tells you that the time has come to fulfill the prophecy and unite the two sides of Xeen. You have to

• turn on the machines at the corners of Cloudside
  
• wake the sleepers in the Elemental Planes in Darkside
  
• rescue Prince Roland from Alamar's Castle
  
• open the way to the Cloud world above Darkstone Tower

Most of the dungeons in this section are located in the world of MM4 (I'll call it Cloudside), but count as if they were in Darkside (you'll notice that if you cast Town Portal). This is also the case for the Dungeon of Death.

This is easy. Use the Teleport spell to reach the reflectors in the corners of Cloudside.

Enemies: Fire Blower, Tidal Terror, Whirlwind, Earth Blaster
You reach the Elemental Planes from the corners of the Skyroad. When you are asked what you seek, type the name of the element (e.g. "Fire"). In each plane the Sleeper is sitting on a throne near a corner, and near the opposite corner there is a hole where you can return. Cast Protection against Fire for the Fire Plane and Levitate for the Air Plane.

Enemies: Frost Dragon, Acid Dragon, Fire Dragon, King Dragon
You find the Key in the dungeon of Alamar's Castle (13/3).
Alster the Druid (Lvl 1 6/5) asks you to bring him a Dragon Egg. You find it at Lvl 2 (4/10). When you bring it to Alister, he gives you 1 mill. XP, but then he turns into a Dragon King and attacks you.
Here you can find 4.000.000 GP, and the books at Lvl 4 give you 10.000.000 XP each! (Don't spend the money for training - you'll soon get lots of levels, and you should save 4.000.000 GP for the Southern Sphinx.)

Enemies: Cloud Dragon, Green Dragon, Phase Dragon, Energy Dragon
The Dragon Power Crystals will give you +3 or +5 Levels permanently. In the corners there are books which give you a clue about the password - let the character with the highest intelligence read them. The well at (23/30) gives you +50 Levels temporary.
When you know the password (but not before!), talk to the statue at (15/30). You will get the Silver ID.

Enemies: Onyx Golem
You find the Key in the dungeon of Alamar's Castle (11/9) after you have got the Silver ID.
Look at all statues, then read the letters (in your auto notes) from top to bottom. It's a message from New World Computing.
If you look at the map, you will once again notice that the walls form numbers or letters. You have to ring all gongs, but be careful! You will lose HP, and Onyx Golems will attack you (they take away your SP). The skull at Lvl 4 (7/9) asks you a question - answer "120" and take the Gold ID from the display case at (9/8).

Enemies: Annihilator, Autobot (if you didn't already defeat them)
Show the Silver ID to the Skull in the dungeon at (15/5). He opens a new way. At (11/9) you find the Key to Darkstone Tower, and the Skull at (15/9) opens the next passage when you show him the Gold ID. There are 2 Xeen Power Juices (+ 5 Levels permanently), and in the coffin at (13/15) you finally find Prince Roland! He thanks you for rescuing him and gives you the Amulet of the Southern Sphinx, where you can find something to open the way to the Cloud world.
BTW, you can enter Castle Alamar from the Skyroad (A1 10/4), but this entrance is guarded by the Mega Dragon, which is almost impossible to defeat. Good luck!

Enemies: Ghost Mummy, Dragon Mummy, Phase Mummy
You get the Key from Prince Roland when you free him.
To open the coffins at Lvl 1, you have to be very strong, and the opening character will be cursed. there are some nice items nevertheless. The Super Elbalming Fluids in the barrels give you 2.000.000 XP, but have negative effects like Death. The other barrels are useless.
In this Level there are many traps. The candles at (5/10) and (9/10) sell you protection from the swinging axes and the guillotines for 2.000.000 GP each, which I would highly recommend if you want to explore the basement.
The left way from the entrance takes you to the stairs to Lvl 3 (which is in fact the basement) after crossing a large room full of traps. Downstairs you find some clues about the name of the Sphinx and some potions which give you +5 Levels permanently. But there are also lots of Dragon Mummys which are very dangerous. (You can skip this Level and look in the Puzzle Spoilers Section.)
Now take the right way. At (7/15) you will be asked for the name of the Sphinx. But you can't pass if any of your characters is cursed. Talk to Picard the Aged at Lvl 2(7/3). He will give you the Chime of Opening in exchange for the Widget, which you got from Halon (B3 9/6). The coffins in this Level contain only Phase Mummies.

With the Chime of Opening you can break the seal and enter the clouds. Follow the road, use the Rest Stops if necessary and don't forget to renew the Levitate spell. When you reach the Pyramid, you can watch the ending sequence.

Enemies: Skeletal Lich, Annihilator, Autobot, Devil, Demon, Lord Xeen
This Dungeon is completely optional! You get the Key from Sandro in Necropolis.
Lvl 1 is one of the funniest dungeons I have ever seen: it's a crossword puzzle! Read the long story at the statue and write down the green words. Then check the scrolls for the definitions and "fill in" the matching words. If the answer is correct, the water in this row will disappear. When you have finished the puzzle, you can proceed and get +5 levels.
In Lvl 2 you can destroy the Shrines to get millions of XP, but DON'T destroy the Shrine of Ultimate Evil at (2/20)! Proceed and set all dials to 2. A new way will open in the SW.
In Lvl 3, you have to ring the gongs at (2/3), (2/28), (29/4), (27/30) and pull the lever at (17/3). This is a bit complicated since you mustn't touch the treasure heaps, and teleport doesn't work.
In Lvl 4, you must fight lots of Lord Xeen Clones! I hope you kept your Xeen Slayer Sword. (With the "I lost it"-cheat you can get a Xeen Slayer Sword for every member of your party, which will help you greatly.) You can destroy the Xeen Machines at (2/3), (3/29), (27/3) and (28/29) to get 5.000.000 XP, but you must jump over the trap fields. In the Control Room, type "Computer" to receive a cryptic message :-)