Warcraft III: The Frozen Throne/Undead strategies

The Death Knight is generally used as the 1st hero because of a) Death Coil heals your own troop, and unlike Human Paladin's Holy Light, could be used against most creep and b) Unholy Aura is often considered the best aura overall, because it boosts rushing speed and healing speed, which also stacks with other Heal Over Time. Death Pact is OK, but is shadowed by the uberity of Death Coil and Unholy Aura. Animate Dead is more of a situational move, you should only use this when there are very powerful corpses on the ground, such as Human Knights, Undead Abominations, Night Elf Bears, or Orc Taurens.
 * Heroes

Dreadlord are only used against noobs. Sleep may seem like a powerful move at first, but everybody and their grandmother knows that you can wake up your own unit by attacking them with another unit. Carrion Swarm is so-so at best, and Vampiric Aura doesn't really work if you use crypt fiends, limiting your stratagy. However, if you somehow do get the Dreadlord to lv 6, Inferno is the best ultimate for Undead, it's like having a permanate LV. 6 Chaos Damage Magic Immune wrecking house.

Lich is going to be your damage output hero. Being weak by itself, the Lich has Frost Nova, which is AOE and useful in all situatons; Frost Shield, which doesn't really do much execpt increase the tanking ability of DK; Dark Ritual, which is slightly more useful than Death Pact but not quite; Death and Decay can kill anything, but it ran on a percent scale, which means it is going to take the same time to kill a footman and a castle, provide it last 20 seconds.

Remember: the Undead should not use neutral heroes. Night elves use Pandaren and Naga a lot, humans might throw in a Beastmaster, but the Undead has all the heroes that are the best for them.

Tactics
There are a lot of different tactics while playing the Undead Scourge, but the most important thing is to scout and counter the tactic of your opponent earlier than he does.

Many Pro Gamer (Professional Player) use a Dual Crypt Rush stratgegy. It`s a strategy which represents the usual Build Order(BO) of the Undeads,so I`ll explain it first.

Start creating three acolytes (optional:create only two and scout with your ghoul after getting enough lumber for building one Crypt,one Altar of Dead and a Ziggurat as well as one Tomb of Relics) and send the Ghoul cut some lumber and two of the three Acolytes to the goldmine,the other one summons a Crypt and a Ziggurat.Then send it to the goldmine as well. After you possess enough lumber for an Altar,start summoning the same and later a Tomb of Relics and another Ziggurat.Summon a second Crypt as early as you can to create more Ghouls (this is why its called Dual Crypt) All the time you must build as many Ghouls as you can.Send them to the wood.If your hero is finished,send them with a right click on your Necropolis and then to your hero.Then buy your hero a nice Necromany Rod in the Tomb of Relics and let the fun begin.

Now you are ready for attacking your enemies base.Try focussing your oppononent`s hero(focus:all your units attack one specific unit) and surround him if he wants to flee (surround:stop a unit walking away by blocking his way with your units).Your Ghouls are faster,if you creeped your hero to level two and skilled him second with the aura.First skill must be the Death Coil.

Against Human
The crypt fiends are useless against human footmen, and they also have militia, meaning that is difficult to challenge them fast. Best hero would be the Crypt Lord, striking with his claws many enemy units, also stunning them, as human footmen. Avoid getting deep into your opponent's base, until his entire army is dead, and then his workers must be eliminated. after that, take out his farms...and that should do it.

Against Orc
Form a team pf 5-6 ghouls (with cannibalize ability) and have a rod of necromancy along your inventory. set rally point of crypt (even 2 crypts would be good) upon the hero, and produce continuously ghouls, and simultaneously upgrading their armor and attack damage. Your army will be superior to the orc's army, and their units have lots of hit points, but weak damage, allowing the hero gaining level really faster. After orc's army is slaughtered, take out his burrows, then he's doomed.

Against Nightelf
As the Nightelfs build units and buildings way slower than you (the perfect UNDEAD!!!) are, build these first: 3 zigurats, 1 crypt, 1 graveyard (for later use) and a tomb of relics. Build an elite team with the Hero you got, 5 ghouls, 3 necromancers (correct my spelling if I'm wrong) and 3 banshees. Research Cannabalize to help with the healing of ghouls, and prepare for the fun! Go near the nightelf's base, hold there till noon (weakest time for the elfs) and attack the hero first, when s/he's dead, the rest is at your hand! IF you have time, research the upgrades in the graveyard! BUT REMEMBER, THIS STRATEGY IS ONLY GOOD FOR 1-on-1 between you and the elfs!

Against Undead
Undead versus Undead is often the single most annoying kind of match up in the game, due to the fact that you can't use Death Coil or Disease (picking up the Death Knight will reduce its functionality, and upgrading disease would be a waste of resources). Your first hero is not going to be the Death Knight, as he is only useful as a Paladin when facing non-Undead. Instead, get the Lich and nuke away.

2on2 with Orc
One of the best hero combos with UD/ORC is BladeMaster (BM) and DreadLord (DL).

The skills you get are Sleep and Vampiric Aura, and Wind walk and Critical Strike.

Sleep and Windwalk is good defense and offense, both the UD and Orc can hold off on their own. In the beginning, the Orc goes BM and grunts, nothing fancy. Then at Tier 2 ( T2 ) you add a Tauraun Chieftan. ( TC ) and a lodge for adept walkers and a little bit more grunts than usual, and some raiders. Get orbs, and lust as well.

The UD goes DL and ghouls and normal tech .. In T2, you can either get Panda or Lich. also, add in some fiends and some banshees. Around that time BM reaches lvl 3. UD doesn´t tech to tier 3 here, except for possession on the rare games against lots of tier 3 melee.

The point is to harass on early game, this strategy is very useful, especially if a Night Elf is going mass hunts. The BM kills the wisps, while the DL and ghouls defend with sleep and surround.

This strategy is very good on Gnoll Wood as well.

Well, GL & HF, micro well.