Warcraft 3: Reign of Chaos Undead 6: Blackrock & Roll, Too!
This is one of the longer missions if you want to complete the side objective, and it's also the first mission in the campaign is go over 70 food!
This is also the mission we get one of the most powerful units in the game, frost wyrms!
I started by killing off 2 gargoyles just to get below 40 supply again. Also, make 2 ghouls so you have a total of 4 gathering lumber.
Start creature upgrades, like the usual.
Make an altar of darkness as well, it is needed to make a black citadel.
You also get the shade, the unit you saw in the first mission. You can use it to scout around everywhere, since there are literally 0 units in this mission that can even see it.
After the first orc attack...
...you will want to destroy the blue base to the west. Also, when you kill the orc heroes, they will drop tomes so make sure you do pick them up.
Also, i forgot to mention, you get a new hero, Kel'Thuzad. He has a powerful spell, frost nova, that deals damage to a few units in an area. He also has frost armor, make sure you cast it on Arthas often.
You can make a few fiends, but don't get too much, you want that supply for frost wyrms.
Make 5 acolytes, now you can go above 40 food.
Make a slaughter house as well.
Also, make sure you upgrade most of your ziggurats to spirit towers since the orcs might attack you while your army is away.
Haunt the gold mine when you have the gold and use the acolytes.
Right after you're done making the acolytes, make a black citadel.
You can go and take out the red dragons to the north, as they might be annoying in the future.
Soon after, get the red dragons to the east.
After you're done with the dragons, you will want to destroy the brown undead base to the south. That will be the next place to make an expansion.
After you're done with the citadel, make a boneyard. Stop making fiends from now on.
Also, you can get a second meat wagon (if you didn't lose the first one) and get the Disease upgrade.
Get the frost wyrm upgrades ASAP and start building more of the dragons.
It's also time to build 5 more acolytes.
I killed off my gargoyles just to have more supply for the frost wyrms. Don't kill any fiends though, unless you have 84. 85 or 86 supply, otherwise just make another fiend to get ~90/90 supply.
While you're building frost wyrms, you will want to destroy the orc base to the west.
Shouldn't be too hard, if anything it should be easier because this time the hero you're against is a far seer, and he won't annoy you with illusions.
Also, be very careful of red drakes attacking your base. I had forgotten to upgrade my ziggurats and i lost 5 acolytes because of that. Make sure you kill it before it destroys the rest of your base.
Also, a frost wyrm cannot take on a red dragon 1v1.
After the base to the west, destroy the one to the north. Should be as easy, as there's another far seer.
After that, go after the red base. It will be the hardest one since he is level 8 and deals a lot of damage.
Funnily enough, the red orcs are the only ones that killed a unit. So be the most careful with them.
Make sure you spread out your frost wyrms, one to attack each building, because they can freeze the buildings, halting production.
After you're done with the red base, you will complete the mission.