The Undead roster is easily the weakest and most restricted roster in the game that have serious issues with scalability. The path that I have designed here is not one that can function as a primary carry army for the Horde. While it is boasts impressive offensive firepower and anti-magic capabilities in the hands of a competent player, it can be easily countered, it is difficult/more intense to use, and does not utilize any higher tier melee units over simple Ghouls. This path is optimized for the Undead Army to be able to purchase Maidens at the 30 minute mark, which hopefully then can transition into the army into one that is a true carrying force.

The Undead roster lacks any serviceable auto-cast spellcasters of their own, often requiring support from Orc support units, and their heavy melee units are much more fragile compared to the other races, even Night Elf.

1. Purchase Skeleton Archers. Upgrade Attack to 6.
    - An absolute must-have in the Undead army. With moderate survivability and exceptionally high damage that is complemented with Frost Arrow which adds a whopping 25 flat damage, Skeleton Archers probably are your strongest offensive unit the entire game until you get Maidens. That should be concerning considering that it is the first unit you should buy. It's stats are exceptionally cost-effective/efficient with high damage output and the ability to delete anything with light or unarmored armor. Tempo Loss: Nonexistent. Gain: Very High.

1.5 Purchase Crypt Fiends and Autoweb
   - A cheap purchase that shares the same upgrade path as skeleton archers, however with their rather reduced damage and larger unit model size, its not a unit you can depend on for doing reliable damage. It's only use is efficient autoweb ability to shut down Alliance air.

2. Purchase Obsidian Statues and Research Destroyer Form.
   - A rather expensive investment this early in the game, they have decent health pool sizes and moderate to low magic damage, their primary function is to do magic damage and dispel enemy units. These units MUST be microed in order to be properly used and are still able to be easily countered or locked down. Tempo Loss: Very High. Gain: High.

3. Purchase Gargoyles and Research the Ghoul Upgrade, Research Lifesteal and Armor Upgrades
   - Again critical air pass comes into play. With both Gargoyles and Destroyers on the field in high numbers this early in the game, you have an oppressive air force if microed properly. Gargoyles you can more or less leave by themselvles because they have high damage and high HP and lifesteal once you have it researched.

4. Purchase Hero/Heroes
   - With an army is incomplete as this, you absolutely need mobility and defense to keep this army afloat and effective. Unholy Aura and Devotion Aura are vital auras you should look for when picking your heroes.

5. Purchase Maidens and Finish Attack/Defense Upgrades
   - Your army will have decent offensive potency that should be enough to net you gold for Maidens by 30 minutes. However, it is an army that does not stay alive long, so it is vitally important to pay attention. You do not want to be in a scenario where large portions of your air units are taken down because they do take a while to respawn and make a good portion of your offensive power. Upon purchasing Maidens you may fill out the rest of your army with appropriate units.

Questions!

Question: What about Necromancers?
Answer: Absolute dogshit. Summoning a bunch of weak skeletons that feed gold/exp, do no damage, and are easily dispatched of with AOE abilities does nothing. Skeletons provide nothing. They are only a negative. Cripple isn't autocast, so it's a useless single target ability that requries additional micro.

Question: What about Skeletal Orcs, Zombies, and Abominations?
Answer: Each of them are rather fragile and not worth their cost. Zombies have small health pools and less armor, Skeletal Orcs have reduced health pools even when there are additional upgrades for HP, and Aboms are also low HP pool that are also rather slow.