Warcraft III: Reign of Chaos/A Destiny of Flame and Sorrow

Mission Objectives

 * Main Quest: The Skull of Guldan
 * Destroy the Demon Gate guarding the Skull
 * Bring Illidan to the Skull of Guldan
 * Main Quest: Destroy Tichondrius
 * Destroy Tichondrius

Starting Units
Illidan controls a decently developed base provided with 2 Huntresses, 2 Archers, and 2 Druids of the Claw.

Summary
Use your starting mine and the mine north of your position to develop a solid fighting force and a defense group of Archers and Ancient Protectors that you can safely leave on autopilot. An ideal force uses Illidan and 5-7 Huntresses/Druids of the Talon, backed up by 6-10 Archers/Dryads, and Ballistas.

Take out the enemy base to your northeast, and fortify your army for a stronger attack on the northwest base. Throw together any other units if you can spare the food, and force your way to the Skull of Guldan in the northwest corner.

At this point, take out Tichondrius at your leisure.

Strategy
Focus on solidifying a defense at your base, and then taking out your enemies one at a time.

Getting Started
First order of business is fending off a Level 8 Satyr and his fellows.

Illidan, level 7, is a powerful tank. He'll finish the first enemies with a little support from your starting units. Mana Burn is essential against enemy spellcasters. Take advantage of its short cooldown. Immolation works well to whittle down your melee foes.

A second gold mine lies just north of your position. The guards can be taken out with your starting force. Still a third lies to your left in the swamps, but you'll want to solidify a defense first.

Build up Moon Wells at your base entrance for easy healing. When resources are comfier, build an altar and upgrade your Tree of Life.

Start researching for your attack force of choice. A healthy Archer-Huntress combination is recommended, bolstered by Dryads and a few Druids of the Claw.

Defense
Your main enemies will be the satyr-skeleton-treant force that makes up the corrupted Ancients. They have two bases, one to the west and one to the east. They attack your base from the bottom two exits. Since they attack in mobs, they're easy to pick off, but casters like the Hellcaller are fond of raising the dead.

Tichondrius's patrolling forces are Doom Guards, slow lugs that fall easily under Archer fire. They're easy to take out, but have annoying spells. Similarly, the Felhounds may terrorize your Druids, but against pure infantry, the Legion is a pushover.

Leave at least a couple of Archers, Druids of the Claw, and clusters of Ancient Protectors behind as base defense. If things get out of hand, call back your attack force with a hasty Scroll of Town Portal.

Taking Out Half the Problem
Tichondrius can be killed without taking out the corrupted Ancients, so attacking the latter is optional. But highly recommended.

The first corrupted Ancient base lies near the north east of your position, either east of the second mine, or east and north of your original base. Engage cautiously. Using Roar in battle can make a difference. Pull back your units and let Illidan take the brunt of damage. Cast Rejuvenation when hit points drop around the halfway point.

Kill their Skeleton King and clear the satyrs out. With an enemy taken out, base defense should be drastically less of a hassle.

The Other Half
Assemble a strike force similar for your first attack. This base is to the west of the second mine, or west and north from your original base.

You can bait the enemy out by harassing it with Illidan, or edge in, prepared to suffer massive damage. A solid wave of units will come out after you. The Hellcaller will bolster his forces with more raised dead if you let him. It's basically the same affair with the previous base, but busier.

If you crush the satyrs, you're free to deal with the Skull of Guldan.

The Demon Gate
Replenish your army as you see fit, ideally fitting in more than a few Dryads. Head up to the Skull, clearing out minor annoyances like Felhounds, Treants, and Doom Guards. Mana Burn is useful here, considering the Felhounds' own Mana Burn and the Doom Guards' spells.

At this point you shouldn't be worried about losses, if you've taken advantage of the five gold mines available to you. Head up and crush the Gate.

Killing Tichondrius
From the Skull of Guldan, you can head left to Tichondrius. Shamelessly spam your army into high upkeep and prepare to finish the mission at one fell swoop.

You can take out the Infernals and Doom Guards if you please, or focus all your attention on Tichondrius. Preferably the former. (Damage types that aren't Chaos will deal 1 damage only to Divine armor.) Illidan bolstered with Roar can deal good damage to Tichondrius.