Kendric

Once inside the area, you can choose <easy> or <hard> mode to explore, and it is a very peculiar area to explore (as none of the rooms count towards your explorers rating, though you will encounter roughly 230 rooms within both easy and hard modes).

You'll notice that the Hard level is exactly the same as the Easy level with the exception of the one room heading north (2 west from the northeast corner) which takes you into the 3Kraft Castle area.

1. Once you're inside the area, travel <select snow, e, s, kill ein>

   40k : Ein

2. <search snow, open trapdoor>
3. <select building, w, jump through window, kill lee>

   42k : Jan Lee
   19k : Leifang

4. <open grate>
5. <select cliff, kill wong>

   48k : Brad Wong

6. <jump, jump, jump>
7. <select cage, se, kill bayman>

   45k : Bayman
   27k : Leon

8. <w, open door>
9. <select aquarium, kill bass>

   37k : Bass
   36k : Tina

10. <climb ladder, get urchin, swim out>
11. <select forest, e, kill hitomi>

    55k : Hitomi

12. <cave, search leaves>
13. <select final, kill omega>

    74k : Omega
    
    Omega drops an energy weapon:
    Energy Staff (enchanted)
    This weapon is capable of emitting contained energy in two directions forming a deadly energy staff. The handle is somewhat heavy, but the blade has no mass. You feel like somebody out of some sort of star battle movie trilogy when you hold it.
    This weapon is in excellent condition.
    This weapon deals magic damage.
    This weapon's classifications: 50 (energy)
    This weapon gains benefits from your polearm weapon skill.
    You must be level 25 to wield this weapon.
    It looks heavy.

14. <end game>
15. Return to Chaos: <gameover, n, e, out, 2w, n, e, n, 2w, 3e, vortex>

TLDR, provided by Giorgi
It is indicated that the area layout (map) for this area changes each reboot, but the given layout for that boot is the same for all three levels (normal, nightmare, hell). If you've played the game, Diablo II before, you'll have an easier time going through the area.
Much like the game, you can open up the next area by following the quest line from the begining town. You just need to talk to the people in the town. The healer starts it off, then you have to find the den of evil, you go back and then someone will send you to do something else, etc. Once you finish the quests for that area you can <say leave> to go to the next area. The next area is great xp on nightmare and hell levels.

STEPS TO UNLOCK COW AREAS, PROVIDED BY FLUFFY and KONG

1. Whether you're in 'Normal', 'Nightmare', or 'Hell', the following steps should be the same.
Once you enter the area, if you see the NPC, Cain, and 'A red portal', someone has already opened up the entrance to the cows. Skip everything below and just enter portal.
2. Hopefully you will have entered immediately inside the Rogue Encampment. Find the <hut>.
3. Once inside the hut, wait for Akara to greet you. <say evil> and she will ask you to find/kill corpsefire.

   Akara examines you closely.
   Akara says: I am the high priestess Akara. There is a place of great evil nearby.
   'evil
   You whisper to Akara: evil
   Akara says: The den of evil is a source of peril for our land. Cleanse the foul creatures from our land.

   Note: If Akara does not say the following line, just leave the hut and re-enter it.

   Akara says: I await the destruction of the evil zombie Corpsefire.

4. Find the 1st set of crossroads outside town (example: w, e, n) and follow one of the paths. Your goal is to find the entrance to the cave. If you find another 3 room intersection (example: n, s, w), backtrack and take another path
5. Once you find and enter <cave>, you'll appear in center of the cave
6. There are 4 paths in each of the cardinal directions. While traversing one of the paths, you will find corpsefire (aggressive mob)

   Normal Mode - 24k : Corpsefire
   Nightmare Mode -
   Hell Mode - 879k : Corpsefire

7. Return to the center of the cave and travel <out>
8. Return to the <hut> (from step 1) with Akara.
9. Once inside the hut, let Akara talk.

   Akara examines you closely.
   Akara says: You have destroyed Corpsefire! Thank you so much. Take this ring as a token of gratitude.

10. <out, training>

    Kashya smiles at you warmly.
    Kashya says: I am Kashya. A foul presence has come to the land.

11. <say presence>

    You whisper to Kashya: presence
    Kashya says: Go to the graveyard and destroy Blood Raven.

12. Similar to the previous step, now find the 2nd set of crossroads outside town (example: w, e, n) and follow one of the paths. Your goal is to find the entrance to the crypts. If you find another set of crossroads (example: n, s, w), backtrack and take another path
Note: The Blood Raven has also been known to be found in the room with the crypt exits, allowing you to bypass trying to find it 'inside' the crypts.
13. 1. <enter crypt 1>, follow the path until you've killed a Blood Raven. If you do not find the Blood Raven, return to the entrance of crypt 1 and travel <out>
    2. <enter crypt 2>, follow the path until you've killed a Blood Raven and then return to the entrance of the crypt. Travel <out>

    Normal Mode - 40k : Blood Raven
    Nightmare Mode -
    Hell Mode - 724k : Blood Raven

14. Return to the <training> room with Kashya.

    Kashya smiles at you warmly.
    Kashya says: You have defeated Blood Raven! Thank you so much. Would you like to recruit a hireling?
    You say: hireling
    Kashya says: What type of hireling would you like to recruit?
    Rogue, Mercenary, Sorcerer, or Barbarian.
    You say: sorcerer
    Kashya says: I require the sum of 1000 gold for a hireling.
    You can "recruit" the one you want.
    recruit sorcerer
    Achilles arrives.
    Kashya fetches a mercenary for you.

    At this point, I'm not sure why/which recruit is needed (if needed at all).
15. <leave, hut> ...wait for Akara to greet you.

    Akara examines you closely.
    Akara says: There is an evil demon named Andariel.

16. <say demon>

    You whisper to Akara: demon
    Akara says: Andariel must be destroyed. Seek her out in the catacombs.

17. <out>, and now travel to the 3rd set of crossroads (example: n, s, e). While attempting to locate Andariel, if you come across a tree, <search tree>. You should now have 'A Scroll of Inifuss' in your inventory.
    
    If you come across 'A scroll of town portal', <get scroll> (these may randomly load on mobs).
    Note: This may take quite a bit of travelling before you find Andariel. You should come across another intersection that leads to the monastery, this is the path you want. Once you find Andariel, <kill andariel>

    Normal Mode - 47k : Andariel
    Nightmare Mode -
    Hell Mode - 1.1M : Andariel

18. Return to the hut. If you come across a waypoint, you can <travel rogue encampment> to get there faster.
19. Once you're at the encampment, travel <hut>

    Akara examines you closely.
    Akara says: You have slain Andariel! Thank you so much. I know I am not supposed to give this to you, but I sense you will understand in time.

    You should now have 'A Horadric Cube (open)' in your inventory.
20. If you did not come across the room with the tree earlier, attempt to find it now and <search tree, get scroll>, and then return to the hut. If you already have the scroll, proceed to the next step.
21. If you did not come across 'A scroll of town portal', attempt to find it now (or at some point before step 29) and then return to the hut. If you already have the scroll, proceed to the next step.
22. <out, travel stony field>
23. With the 'Scroll of Inifuss', <look at symbols, read scroll>

    look at symbols
    The five symbols are a horizontal line, a vertical line drawn down, a vertical line drawn up, an equals sign, and a horizontal zero.
    read scroll
    Suddenly the symbols and glyphs on the scroll form meaningful words and you recite them.
    A red portal rises from the ground.

24. <enter portal>
25. You should now be in a small rectangular area. Travel around until you locate an Undead Wirt. <kill wirt>

    Normal Mode - 57k : Undead Wirt
    Nightmare Mode -
    Hell Mode - 573k : Undead Wirt

26. <get leg>
27. Travel to the center of the rectangular area and <kill mage>

    Normal Mode -
    Nightmare Mode -
    Hell Mode - 410k : Horror Mage

28. <free cain>

    A man in a cage yells "Help!"
    free cain
    You say: Deckard Cain, if you value your life, leave here immediately! Cain says: Thank you for freeing me adventurer, I will meet you at the rogue encampment.

29. Return to 'A glowing red portal', <enter portal, travel rogue encampment>
30. Now that you have 'A peg leg', 'A scroll of town portal', and 'A Horadric Cube' in your inventory, <put leg in cube, put scroll in cube, combine>
31. If the portal to the cow area was alraedy opened, you'll see

    put leg in cube
    You put the A peg leg in the Horadric Cube.
    put scroll in cube
    You put the A scroll of town portal in the Horadric Cube.
    combine
    Nothing seems to happen.

32. Once you're inside CowVille, class sizes are as follows:
    Baby Mode (not part of Diablo II, accessed via CowVille entrance) -
    Baby Mode - 42k : Baby Cow King
    Normal Mode - 82k : Normal Cow King
    Nightmare Mode - 1.5M : Nightmare Cow King
    Hell Mode - 7.4M : Hell Cow King

GEAR
As the cow kings increase in difficulty, the gear they drop also increases in AC.
Baby Mode - Delicate gold crown (tarnished): 6 edged, 6 blunt, 8 electric, 6 mind
Normal Mode - Delicate gold crown (shiny): 8 edged, 8 blunt, 10 electric, 8 mind
Nightmare Mode - Delicate gold crown (sparkling): 10 edged, 10 blunt, 12 electric, 10 mind
Hell Mode - Delicate gold crown (radiant): 18 edged, 18 blunt, 19 electric, 18 mind

Information missing for this area yet. Complete the area feedback form if you'd like to add data.

Detailed information is not available for this area yet. Complete the area feedback form if you'd like to add data.

Note titled 'Mystic Seal Expansion (Thyros, Tue Oct 10 20:07:42 2006):

Arlane the Sorceress has been devoting her considerable intellectual faculties toward the study of a crystal matrix hidden in the hills of the Realm of Fantasy. It would seem she's finally close to cracking the enchantments protecting it.

This area is the product of a long collaboration among Tramane, Kendric, and me. Hopefully there will be more here in the future... although I'm certain you will find there's quite a lot accessible now.

Hints:
Don't try this unless you're at least level 50.
Be careful - some parts of the area and some monsters can bring rapid flaming death even to parties of level 100+ players.
Make good use of the "rating" command - different parts of the area have been rated according to difficulty.
Bring lots of light sources.
Talking to npcs is usually a good idea.

Enjoy.