Warcraft III: Reign of Chaos/Human units
Heroes are a new element to Warcraft and are extremely powerful units. Up to three heroes can be recruited. All heroes are created (and recreated, in the event they die) at the Altar of Kings.
The Paladin is a melee combatant but isn't as powerful as some other heroes, such as the Blademaster or the Demon Hunter. He is more akin to the Dreadlord in being a support hero with a melee attack. His spells make him a good choice for beginning players, who can use the Paladin's Holy Light ability to heal, and Devotion Aura to boost the armour of his units.
There are a few different ways to build your Paladin - some players choose to invest in Holy Light and Devotion Aura, then get Resurrection at Level 6. Others players go Holy Light and Divine Shield with a point or two in Devotion at higher levels. While you could go a mix of Divine Shield and Devotion Aura it's better to use Holy Light.
Holy Light is a spell that causes a holy beam of light to pierce the target. It can heal a single organic unit such as a footman, rifleman, or knight, but it cannot heal mechanical units like Gyrocopters. Holy Light can also be used as a weapon against undead opponents, damaging them for half the amount. Since the Paladin has a melee attack, Holy Light can allow him to strike aerial undead units such as Gargoyles and Frost Wyrms.
Divine Shield allows the Paladin to become completely invincible for an amount of time. In this state it cannot be targeted by enemies, so enemies typically will run away when Divine Shield is active. At higher levels, the spell lasts longer. It's also effective in allowing you to run your Paladin away from threats. When it wears off you can use an Invisibility Potion to get away. Divine Shield cannot be deactivated.
Devotion Aura boosts the armour of nearby units. Naturally, the more units around the Paladin, the better Devotion Aura is. Players often improve this along with Divine Shield of Holy Light.
Resurrection, when triggered, targets the corpses of dead allies and brings them back to life. Naturally, this skill is best used when there are at least six powerful, and recently slain allies nearby, such as Knights, Tauren, or Bears.
The Archmage is a spellcasting hero, capable of creating destruction through carefully crafted spells. As a caster it is extremely vulnerable to attacks and should not be anywhere without escort. Under no circumstance should you allow the enemy to surround your Archmage.
Skill point spending tactics include Water Elementals combined with Brilliance Aura, or Blizzard combined with Brilliance Aura. So the standing question is: Water elementals, or Blizzard? Both have their strengths and weaknesses. In smaller games, or if you intend to use a lot of melee units, try to use Water Elementals instead - Blizzard has an annoying tendency to harm your own units as well as the enemy's. That said, Water Elementals can be easily dispelled by anti-spellcasting units like Dryads. Typically players use Water Elementals in 1 vs. 1 and 2 vs. 2 and use Blizzard in 3 vs. 3 and 4 vs. 4.
It typically isn't hard to kill an archmage, especially if you use an immobilizing spell like Entangling Roots or Ensnare. All that is required afterwards is to surround the Archmage and attack it normally.
Blizzard summons multiple waves of freezing icicles that damage everything in their area of effect. Higher levels increase the number of waves and the damage each wave does. Since Blizzard affects your units and the enemy's, try not to use it in a melee - try instead to cast it on the enemy's ranged support. Note that Blizzard must be maintained, and if the Archmage moves or is forced to stop casting Blizzard, you won't receive its full effects. Blizzard also does not harm magic immune units like Dryads or units with anti-magic shell. This can allow you to cast it safely if an undead ally uses anti-magic shell on your footmen - then you can shower them with Blizzard and not worry about them.
Water Elemental summons a giant hulking form of water that acts as a short-ranged archer. Its primary role is to provide additional damage and to give the enemy something to shoot at besides your troops. A level 3 water elemental can be rather difficult to vanquish. It can also strike aerial units. Enemy heroes, however, can gain experience from killing water elementals. Water elementals, as summoned units, can be dispelled and only last a short amount of time.
Brilliance Aura works in conjunction with spellcasters and other heroes. It increases mana regeneration for all nearby units.
Mass Teleport can be an extremely deadly spell, allowing unprecedented mobility for the Humans and their allies. Only obtainable at Level 6 and above, Mass Teleport essentially allows the Archmage to teleport himself and up to 24 units - a veritable army - to any friendly unit or building. Obviously this allows for devastating surprise attacks, especially late-game when the enemy is more focused on his or her expansions and less so about their main town. You can even mass teleport to invisible units - have a Sorceress use Invisibility on a unit, run it into the enemy base, and then use this spell on them. Then laugh at your opponent as he stares stunned at the army materializing into his base.
 Mountain King
For sheer power, the Mountain King has all the human heroes beat. He is also an expert at chasing down enemies thanks to his Storm Bolt ability, and Thunder Clap can turn the tables if he's surrounded by cheap enemies.
For skill point spending, most players focus on Storm Bolt or Thunder Clap along with Bash if necessary, holding out for Avatar.
Storm Bolt has the Mountain King hurl a hammer at a target, stunning it and causing considerable damage to it. The stun effect particularly makes Storm Bolt a powerful hero killer - when an enemy hero attempts to flee, use this skill to stun them. Then surround them with your army, and then attack. Storm Bolt's lack of area of effect detriments it against multiple opponents, but that's what Thunder Clap is for.
Thunder Clap has the Mountain King slam the ground, causing area of effect damage and slowing the enemy down by 50%. The higher the skill level, the more damage this does. At Level 3 it can eliminate multiple low-levelled enemies in a single strike, allowing the Mountain King to turn the tide of battle when pitted against multiple small opponents.
Bash is a passive skill that does not need to be activated. When the Mountain King has Bash, he can stun enemies and cause additional damage with his normal attack. The higher the skill level, the higher the chance of this skill occurring, up to 40%.
Avatar is the Mountain King's ultimate spell. Obtainable only at Level 6, the Mountain King becomes enormous. The Mountain King 5 bonus armor, 500 bonus hit points, 20 bonus damage and spell immunity while the skill is active. This skill is best used when a group of enemies are pinned in a battle and are unable to flee it, or against a base with a lot of towers - the extra hit points and the bonus armour really help the Mountain King act as a shield for the smaller units.
 Standard Units
Standard units are units that can be built at usual unit producing structures, like Barracks. There is no limit to the number of standard units you can field, aside from that dictated by your food cap. They are also considerably weaker than heroes and do not gain experience.
|Armour Type||Medium (As Militia: Heavy)|
|Abilities||Call to Arms, Return to Work|
|Upgrades||Forged Swords, Plating|
Peasants are the standard worker units for your army. They perform extremely useful tasks - namely the gathering of resources and the construction of structures that assist the rest of your army. Up to five peasants can work on a gold mine - any more are a waste (although some players insist that six is most effective). Peasants also can gather lumber from trees, and construct buildings.
Peasants are unique in that only they can cooperate in building construction. At the cost of a few extra materials, you can assign multiple peasants to build a building, and it will be constructed faster. The downside to this is that the peasant is vulnerable while the building is being constructed.
When the town is under attack, Peasants can transform into Militia for a period of time. This is activated by using the "Call to Arms" ability from the Town Hall, or by giving the order to each individual peasant. As a militia their attack nearly doubles, they gain 4 armour, have a faster attack rate, and better overall statistics. They only last for a limited amount of time before automatically reverting to peasants, but it is typically long enough for them to defend against an attack. Their military tenure can be cancelled prematurely by using the "Back to Work" ability from the Peasant (sending just that peasant back) or from the Town Hall (ordering all Militia back).
|Upgrades||Forged Swords, Plating|
Footmen are your standard melee soldiers. Armed with broadswords and kite shields, Footmen are the units a new hero wants on his or her side for aid. They are otherwise unremarkable, aside from their special ability.
Defend is a skill that slows the Footman down, but renders him almost immune to arrows and piercing attacks. This makes Footmen extremely deadly against towers, archers, and other standard range units. Defend has no effect at all on standard attacks, such as against ghouls, huntresses, and siege units like meat wagons.
Defend does not require mana and can be activated and cancelled at any time. Ensure to deactivate Defend when the footmen are not engaging ranged units.
|Upgrades||Gunpowder, Leather Armour, Long Rifles|
Riflemen cause considerably more damage than footmen, but they are less capable of receiving it. As ranged units they are very susceptible to melee attacks, but are more effective against spellcasters. Riflemen replace archers as backup ranged units for footmen.
Their Long Rifles upgrade allows them to strike at a longer range than normal, and are a necessity if you intend to use them for long. Also as ranged units their prowess against flying units remains almost unparalleled.
Riflemen work well in conjunction with a Paladin, since his Devotion Aura allows for increased armour and Holy Light can be used to support the Riflemen a little more. When fully upgraded Riflemen will prove to be a threat against any unit.
|Upgrades||Forged Swords, Armour Plating|
Knights are the heavy melee unit of the Human arsenal, comparable to the Orc's Tauren, the Night Elves' Bears, and the Undead Abominations. They can be considered pretty much footmen with additional speed and agility, but they cannot use Defence and therefore are a little more vulnerable to archers. Their primary enemy, however, is spellcasters - their heavy armour means they'll take additional damage from magic attacks. As melee units they can't strike aerial enemies.
|Abilities||Heal, Dispel Magic, Inner Fire|
|Upgrades||Adept and Master Training|
Arguably the ultimate support spellcaster, Priests sport a basic Heal spell which recovers the HP of nearby organic units. Although it cannot heal itself, Priests can heal each other. By right clicking on Heal, it is used on any wounded allies automatically.
Dispel Magic effectively destroys all magic buffs in a target area. It is not as selective as the Dryad's Abolish magic, which keeps positive buffs on friendlies and negative buffs on enemies. Regardless, however, Dispel allows Priests to cause considerable damage to summoned creatures, such as Water Elementals, Treants, and especially Skeletons - typically numerous in number buy have low HP.
Inner Fire is the Human response to the Orc Bloodlust. It does not provide as much of an attack bonus as Bloodlust, nor does it provide the speed bonus, but it does provide a considerable armour boost as well as additional firepower. It can be automatically cast on any enemies taking fire. Like most buffs, however, it can be dispelled.
Aside from their powerful support spells, Priests can be used as combatants in their own right. Their magic damage and unarmoured armour type allows them to cause considerable damage to units with heavy armour - most melee units, including Grunts and Footmen.
|Abilities||Slow, Invisibility, Polymorph|
|Upgrades||Adept Training, Master Training|
Sorceresses are the offensive version of the Priests. They start with the basic spell Slow, which naturally slows down the target unit. Its applications are obvious - to allow a superior force to chase down a target. Slow is often used on retreating heroes, or retreating heavy and expensive units like Tauren or Knights. Slow also does not require a lot of mana - at full training the Sorceress can slow as many as 8 units consecutively.
Invisibility is another spell that works wonders for getting units into places that the enemy doesn't expect, such as into his town. Although it doesn't provide any bonus damage when attacking to break invisibility (like the Blademaster's Wind Walk) Invisibility can be applied to practically any unit. It is most devastating when used with an Archmage's Mass Teleport. Invisibility allows a player to run a single unit into an enemy base, past all base defences. This will allow the Archmage to target it with Mass Teleport, and let an entire army materialize into the middle of the enemy's base.
The final spell in the Sorceress' arsenal is Polymorph. Originally used in Warcraft II by mages, it transformed a target into a sheep for an indefinite amount of time. Although Polymorph's abilities have been lessened, it remains a force to be contended with. It still transforms a target into a sheep (or a flying sheep when used against flying units) for a minute. It also reduces the target's armour to Medium, making it more vulnerable to melee attacks. The enemy player can move the sheep, but it is greatly slowed and cannot attack for the spell's duration. It is the perfect counter for heavy melee units.
Even without these spells, however, sorceresses prove useful against melee units with Heavy armour. Their Unarmoured armour type allows them to receive very little melee damage in return.
|Upgrades||Gyrocopter Bombs, Gunpowder, Plating|
An improved version of the Flying Machine from Warcraft II, this version has air-to-air machine guns for engaging flyers. Its piercing damage and rapid rate of fire make it extremely effective against other flyers. Additionally its heavy armour means that units with a melee air attack - like hippogryphs and gargoyles - will have a hard time damaging it. Heavy armour remains, however, weak against spellfire. Additionally it cannot return fire against ground units unless it is upgraded with gyrocopter bombs. The bombs, however, cause Siege damage, making them most effective against buildings. Even then it simply does not pack enough firepower to cause considerable damage unless in large groups. This makes the Gyrocopter almost useless against ground targets - its main role is and always will be scouting.
Its True Sight ability allows it to detect invisibile units, making it useful in detecting these - however, the Humans have the Magic Sentry upgrade that allows its towers to detect invisibile units. So unless you have a mobile need for detecting invisible units, use your money elsewhere.
 Mortar Team
|Upgrades||Leather Armour, Gunpowder, Flare|
A replacement for the human ballista from the previous game, Mortar teams serve as ranged siege ability for the Humans. Their mortars cause heavy siege damage to their targets from extreme range, allowing them to strike buildings from afar for massive damage. As siege units, however, they have a minimum range and will have difficulties surviving in close quarters.
Their special ability is the Flare, which allows them to fire a single shining flare to any point on the map. The flare reveals the fog of war in its vicinity, as well as any invisible units. Flare has a very long cooldown.
 Siege Engine
Originally called the Steam Tank, the Siege Engine is a short-ranged anti-building weapon. It is incapable of training its gun against enemy units, but its armour is considered Fortified - meaning that like a building, the only way to cause considerable damage to it is to use siege weapons like ballistae and mortar teams.
Siege Engines, however, are large and have difficulty pathing around large groups of enemies, and prevent them from reaching their targets. To employ them effectively, your best bet is surprise. Hide several siege engines in the corner of a map, and when you have enough of them, send them in. Have them target mission-critical buildings like their town hall and barracks.
As mechanical units Peasants can repair them. A few peasants can help keep your Siege Engines alive long enough for them to complete their missions.
 Gryphon Rider
|Upgrades||Forged Swords, Leather Armour, Storm Hammers|
Gryphon Riders were favourite units in Warcraft II and make a reappearance here. They are somewhat less powerful than before, but are still definitely a force to be reckoned with. Their magic type damage lets them cause heavy damage to melee units like Footmen, Tauren, and Knights. Their low HP and weakness to ranged attacks makes them more supporting units than primary attack units. The Storm Hammers upgrade lets them strike units behind them, much like in Warcraft II.