If you scope this realm out ahead of time, it may on the surface appear similar to Batezek. However, the going is much easier here. This isn't to say that you can slack off, because heroes are already on their way to your dungeon, and as the objective states at the beginning, you must be very careful when exploring.
Build your Basic Five absolutely as quickly as possible, keeping your dungeon centered tightly around the Dungeon Heart. As you mine out areas near your heart, you'll get some frightening messages about tunneling into new areas - these are just small caves, a trick meant to scare you. Ignore them and continue building.
The gold veins to your west and east are safe to completely mine out, however you may wish to leave the outermost part of the western one in order to delay some tunnellers who will visit soon. Though you can see some gems to your south, they are protected and you will not be able to claim them immediately. If you tunnel south toward them, however, you will break into a small cave about halfway there which contains the first two of five level five Skeletons in this realm and a valuable level 3 Imp. Due to your need for speed and protection, I would claim these as soon as possible rather than waiting for your portal max to be hit. It doesn't matter what type of minions you have so much as how strong they are.
If you want, you can also tunnel for the northern gold vein, which in its center contains the other three Skeletons and a level 10 Imp. To do this safely, you must tunnel no more than thirteen tiles north of the center of your portal, then one tile to the left, then around four or five tiles north, one tile back to the right, and then up and over to the back side of the gold vein. As long as you leave the southern edge of this vein, you can safely mine the gold and claim the creatures within it. With all five Skeletons, you will have a much easier time fighting the hero parties that are rapidly coming.
You can once again attract Tentacles and Vampires in this realm, and again the Tentacles are not worth the training time. Vampires are great, though, so build a large Graveyard and get rid of your Warlocks to make room for them. Throw anything that's not useful for fighting out early on, and see if you cannot sacrifice some Spiders and Beetles for more Mistresses - if the Spiders have trained, it is not a waste, for this will result in a Mistress of higher level when sacrificed.
At around thirteen minutes (it seemed like much less to me), the first tunneller party will approach from nearby to the northeast. Three level 2 Thieves, a level 3 Archer, and their level 2 Tunneller carrying 2200 gold are certainly something you can handle. The trouble is that the cave they just came from also contains an additional two level 5 Archers and three level 3 Dwarves who will follow in the wake of the original party.
Don't wall out the heroes in this realm, as there is very little use to this (it may actually make the realm harder and more irritating in the long run). Let them come to you and deal with them on your own terms. Use your Skeletons to best effect, picking them up and placing them back down if they get into trouble, and pulling them out of battle entirely if their health gets too low. There are twenty of every creature type in the portal pool, so any minions who die in battle are expendable. You can replace them before the next round of heroes visit.
Be aware that the cave which has just opened up to you contains a trap which can kill a lot of your precious Imps. Disarm it properly and keep your Imps busy. This will be true of all the caves in this realm.
At 27 minutes, the next party will arrive from the east-southeast. Slightly meaner, it consists of four level 3 Archers and a level 5 Tunneller carrying 2700 gold. The cave they come from also contains additional heroes: four level 5 Archers and three level 3 Dwarves. By this point you should have several well-trained minions, especially your Skeletons, which may even be level 10 if you trained them hard enough. This will not be a problem.
By the time the third wave arrives, your money will start to become a serious problem. If your minions are powerful enough to deal with three level 3 Monks and a separate group of three level 5 Barbarians, then dig south of the cave where you found the level 3 Imp and two Skeletons and you will break into a narrow cave where the Monks will drop in to attack you. Dispatch them and then break down the unaligned door. The Barbarians will also come out to attack. After that, you are home free with the additional large gold vein and gems. Hollow out some area near the cave to make a Treasure Room (but do so cautiously, or you will open up to some dangerous caves full of more powerful heroes!).
The third wave hits at around 41 minutes, coming from the west-northwest. The party itself is more annoying than dangerous, consisting of a lone level 5 Priestess, her two level 3 Mountain Dwarf consorts, and a level 7 Tunneller with 2300 gold total. The problem this time is the heroes that will again follow in their wake. Expect a serious battle when six level 3 Archers and two level 5 Samurai invade. The Samurai must be made an immediate priority. Do not shy away from using Lightning Strikes, even if your gold is running low. If you have secured the gems, then you can rebuild your treasury in time for the next payday. Try to delay this party from breaking into your dungeon by having fortified along the majority of the western half of your dungeon. The longer it takes them to break in, the more time you have to train.
Once this third wave has been extinguished, which is the only chance that you might lose in this realm, you are finished with the first phase. No more tunnellers will come to visit, apparently having caught on to your ability to deal with them properly. Instead, the remaining heroes of the realm will stay inside their bordering fortresses, and a few will drop in if you go looking for trouble near their entrances. So, for the time being, simply build your strength. Get your idle creatures in the Workshop so that you can build Magic Doors and Boulder Traps. Start placing them in the outer hallways created by the tunneller parties. Suddenly the world feels a lot safer! Remember that your level 10 Skeletons can manufacture - just because they're maximum level doesn't mean that they deserve to loaf around!
The best place to attack first is the southwestern hero fortress at point 1 on the map. On the way to its door you will trigger another party of four level 3 Archers - what a joke. Kill them and keep going. Inside this southwestern keep are innumerable level 7 Priestesses and Dwarves (why do they always hang out together?), and a few level 5 Archers. But more importantly, you will find inside a Treasure Room, Prison, and Resurrect Creature special. If any of your well-trained minions fell earlier, you should use the special immediately. Otherwise, save it and we can use it later to make some Knights.
With the Prison, you can now make more Skeletons or convert heroes to your ranks. With that in mind, the next place you visit should be the northeastern fortress directly opposite on the map at point 2. Inside lumber several level 6 Giants and Barbarians at levels 5 and 7. Some of these can be smashed to bits using their own Boulder Traps if you have no desire to capture them - use a concealed expendable Imp to trigger them while the heroes are in the way.
As you approach the hero door, two level 9 Priestesses will drop in using it. These gals still aren't that dangerous. Deal with them in whatever way you want, and to the north you will find a room that contains the valuable Heal spell as well as two level 7 Thieves just ripe for conversion. You should know what to do with these guys by now. Clang-clang, Keeper.
At this point the realm becomes non-linear. You can choose to attack whatever locations you wish. The remaining heroes hide out in the following places:
When there are five or fewer heroes left living in this realm, a two-stage massive attack will begin. Heroes will drop in all over the realm from all of the action points you've previously encountered (or not encountered, even). It doesn't matter what they are, because you have set up numerous Boulder Trap and Door combos in all of the hallways they can use - right?
For some reason, killing all but one of the Monks when there are again five or fewer heroes will trigger the second wave. This wave is the strongest and includes the Lord of the Land. They use the same spawn points as the first wave and so they try to attack you from all angles. Hopefully you still have more traps waiting for them. If not, you have quite a battle waiting for you. But that's what you trained your minions for, right? Give it to them one way or another and then take a well-deserved vacation. Although, this was already pretty relaxing compared to the previous realm. Good old-fashioned exploration and hero-slaying mayhem - my favorite kind of conquest.