The night elves are truly a mixed bag. They have some genuine advantages in some areas, but they suffer from some serious disadvantages in others. On the whole, they're a relatively powerful race, featuring tough melee and ranged units, along with heroes that are quite weak compared to the other races until they hit the highest levels. As such, playing the elves can be a tricky balancing act. I'll try to make it clear precisely why this is the case in the sections that follow. The following is a list of the topics covered in the remainder of this document.
I divide the game into four phases: (1) startup, (2) early, (3) middle, and (4) late. I do this because each of the phases has its own special feel and its own set of goals. It also provides a framework upon which subsequent analysis can hang, making it possible to give different advice for the different sorts of situations that tend to crop up in each of the different phases. The four phases are demarcated as follows for the night elves.
In all honesty, the phases are a lot more difficult to divide with the night elves than with the other races. I say this because it's possible to leap up the technology tree (no pun intended) pretty quickly with the night elves. I've often had the tree of eternity pretty early in the game because it's utterly crucial to have the marksmanship and moon glaive upgrades if your archers and huntresses are going to be as effective as possible. That delays production of dryads, druids, and hippogryphs, of course, but it can nevertheless be an effective strategy.
Because of this division, however, I wouldn't be surprised if a lot of night-elf games never make it into the late phase. The air units in W3 are interesting, but they are difficult to use well. This is especially true of the largest, heaviest-hitting units as they require so much food and are so slow that they can be ambushed all too easily. The night elves are at a particular disadvantage in terms of air units insofar as their basic air unit, the hippogryph, has no attack against ground targets. This deficiency can be ameliorated by creating hippogryph riders instead, but this too makes little sense, in my estimation, for reasons I shall explain.
At any rate, my favorite phase of the night elf game is the middle phase because the various spell casters that may finally be produced therein are extremely effective supporting units. A good group of huntresses, accompanied by a couple of dryads, and a couple of druids can be devastating, particularly if they have a crack team of archers backing them up.
As with each of the four races, certain features lend themselves to certain tactics better than to others. The following items should be taken to heart when playing the night elves.
More than any other race, arguably, the night elves excel at hit and run tactics at night. This is because all of the female units can simply use their ability to hide. If you can get a night elf fighting force near an enemy base as twilight approaches, bring them up close and attack. Hopefully, the enemy will be forced to burn his portal scroll to get home and defend his base. When this happens, simply hide. In my experience, most players will hang around in confusion for a few minutes, then head out again. Once they've left the area, unhide and resume the attack. Lather, rinse, repeat. Seriously, archers don't do much damage against buildings, but you can sure take down a lot of lumber-harvesting wisps quickly this way. It also doesn't hurt that huntresses are quite speedy units on open ground. They too can make for excellent hit and run raids.
Unlike any other race in the game, the night elves have the ability to uproot their most important structures, which allows them to join the attack or even move to a new location. This makes protecting bases somewhat simpler for the night elves. When I build my first expansion, for example, I will typically build three ancient protectors nearby to help keep it safe. When that expansion's gold mine begins to run dry, however, then I will typically uproot the protectors and start walking them to the next site. That way I don't have to expend more resources for protection of another expansion, unlike all the other races.
Also, when my base is under attack, I am quick to uproot my ancients of war, lore, and wind to help press the attack. They do decent damage, they have quite a few HP, and they can make always be repaired during battle by nearby wisps. Don't underestimate the value of the sentient structures unique to the night elves. They can easily hold off small forces on their own until help can arrive.
The night elves have an embarassment of riches in this department. The huntress units can use their sentinel ability to keep tabs on specific locations. The PotM can summon an invulnerable owl to scout around the map. All female units can hide in the dark, remaining entirely unseen while scouting an area. Heck, even the lowly wisp often goes unnoticed when busy harvesting lumber. Some players don't even bother killing them when found around the map. If you don't have good data on the enemy when playing the night elves, you can bet that you're playing wrong. There just isn't any excuse.
The night elves have the best high-level hero abilities in the game. Sure, the orc earthquake ability is pretty neat, as is chain lightning, but I'll take the ridiculously potent tranquility + starfall combination in a heartbeat. Of course, acquiring these abilities means a lot of time must be spent creeping and/or battling the enemy, but they're easily worth it. Do whatever it takes to get the KotG and/or the PotM up to level six, then use their best abilities in tandem; they'll easily carry the day. Keeping the PotM alive long enough to acquire starfall can be a bit tricky, but it's just too powerful to ignore.
The night elves enjoy three heroes: (1) the demon hunter, (2) the keeper of the grove, and (3) the priestess of the moon. Though all are pretty weak compared to other races' heroes at the outset, they do become very powerful at higher levels. The demon hunter (DH) is by far the melee champion. His immolation ability allows him to deal damage to all the units surrounding him, his evasion ability helps him avoid a lot of blows (and thus stay alive much longer), and he has a pretty powerful melee attack to begin with. In fact, only the orc blademaster does more damage on average.
The keeper of the grove (KotG), in contrast, is somewhat less effective in melee combat, having both fewer hit points and a weaker attack. However, the KotG may attack air targets and has some more useful special abilities. In particular, his entangling roots ability can tie up a melee unit for fifteen seconds, or a hero for three, doing damage in the process. In the startup phase, that can make a big difference, particularly when facing off against small packs of creeps to level a hero. Alternately, when battling on heavily wooded maps, the force of nature ability adds two treants to the player's forces, which is again a non-trivial assistance. Finally, the KotG's thorns aura is downright deadly when used in conjunction with other melee fighters (I recommend a good group of huntress units), and the tranquility ability is simply fabulous for healing a large number of units very quickly. In fact, the tranquility ability is the best healing spell in the entire game.
The PotM is at the other end of the spectrum from the demon hunter; i.e., she's the very weakest hero in combat. At least, she is until she finally acquires the starfall ability. Until then, however, she is useful largely as either a reconnaissance tool, or as an aid to a large group of archers. Her searing arrow ability just doesn't do enough additional damage to be highly useful on its own. At startup, it will take her no less than ten shots to do the same damage that a human paladin or undead death knight can do in a single use of holy light or death coil respectively. Frankly, if she runs into enemy units in the startup or early phases, she's probably going to get clobbered long before she gets those shots off.
When the PotM truly comes into her own is after the player has a large group of archers with the improved bows and marksmanship upgrades. In that case, she is a pretty powerful leader for the group because of her trueshot aura. While the archers do decent damage on their own, they finally become genuinely powerful units when attended by an aura-pumped PotM. When coupled with the starfall ability, such a ranged attack group is downright devastating. The starfall ability causes stars to fall from the heavens that are intelligently aimed directly at any enemy targets in the region. It is one of the best area-effect-damage attacks in the game, and though it takes quite a while to acquire, it's easily worth the effort.
Archers are the first combat unit the elves can build, and they're downright weak compared to the corresponding human and orc units. At the time of this writing, a single archer will always lose to a single human footman or orc grunt. Yes, the archer does more damage on average than either of these units, but the archer is so fragile she'll practically break in two if the enemy sneezes in her general direction.
So what does this mean? It means that you're going to have to build a lot more units than the enemy, or you're going to lose. It also radically affects the choice of initial hero, as I'll explain elsewhere. For the moment, suffice it to say that the night elves most basic unit is at a huge disadvantage compared to the other races, and as such the player must be cautious at startup. Once melee units become available, then archers can become a much more useful unit, but until they have that kind of protection, they must travel en masse to accomplish anything without getting slaughtered.
The huntress is quite a powerful melee unit, especially once the moon glaive upgrade is acquired. The huntress is also the key to keeping your first hero alive, as well as providing some of the best reconnaissance in the game. The sentinel ability of the huntress ought neither be underestimated nor overlooked. Having good intelligence often makes the difference between victory and defeat, and the sentinel ability provides ongoing data essentially for free insofar as you badly need huntress units anyway.
The keys to using the huntress well are (1) pairing them with a good hero, and (2) acquiring the moon glaive upgrade. The best hero for the huntresses, in my view, is the KotG. His thorns aura is a godsend for her, as it forces enemies to take 4, 8, or 12 damage for each strike against a huntress. Since the huntress is always at the front line, typically providing a meat shield for the wimpy archers, this additional damage really adds up quickly. Judicious use of entangling roots and the tranquility ability can help turn huntress units into a seriously deadly wall.
This is especially true if the moon glaive upgrade has been obtained, and it should almost always be researched as quickly as possible in my estimation. This upgrade lets each throw of a glaive bounce off two additional units beyond the primary target. The damage is halved with each bounce, but it still adds up rather quickly. With the combination of the thorns aura and the moon glaive upgrade, a line of huntress units can be formidable indeed.
The ballista is the night elf siege engine. As such, it shares all the faults of siege engines generally; i.e., it's pricey, it's very slow, it's difficult to manage, and it's quite vulnerable to attack. If it seems like I have a pretty dim view of siege units generally, and the ballista in specific, that's close to the truth. I really like using siege units, but it takes a lot of fussy micromanagement to do it well. If the enemy hasn't built much in the way of defensive structures, then I don't recommend using siege units at all. Their forté is clearly long-range bombardment of buildings, and I just don't think they're worth the hassle the rest of the time.
The night elf ballista does have one rather significant advantage over the siege engines of the other races, however, and that shouldn't be overlooked. That is, if one spends the resources on the impaling bolt upgrade, the ballista is far more deadly against clusters of enemy units than any of the other races' siege equipment. With that upgrade, the bolt will pass through whatever unit it hits, impacting any units behind it as well. If you know you're going to be fighting in a pretty narrow corridor, for example, a couple of ballistas can really put the hurt on the enemy in a big hurry. Unless this is the case, however, or you've got a lot of defensive structures to take down, I suggest avoiding the ballista and using the keeper of the grove's force of nature ability to clear trees out of the way.
The dryad is probably the third-best night elf spellcaster. That might represent my bias for powerful melee attacks, but the dryad's powers are pretty impressive. By default, her attacks carry a slow poison that slows enemy movement and attack rates, as well as doing additional damage over time. That's helpful in itself, but it's her spell immunity and abolish magic abilities that really make the dryad useful. The dryad is one of the only units that doesn't have to worry about pesky ice storms or other hero magic. She's completely unaffected by it. This is an annoyance, of course, insofar as friendly units cannot heal the dryad either. That doesn't bother me much because I tend to keep her away from the front lines anyway.
Where the dryad is most useful, I think, is in counter-buffing and dealing with summoned creatures. The dryad's abolish magic ability allows her to remove positive spells from enemy units, as well as remove negative spells from friendly units. This is particularly useful when facing the undead, as their spell casters can otherwise do bad things to front-line fighting units. Additionally, the dryad's abolish magic ability does a rather large amount of damage (300 HP) to any summoned creature. That tends to cut those big, summoned nasties down to size in a hurry. If you're facing the undead, or a feral-wolf-happy orc far seer, then you don't want to be caught without at least a couple of dryads around.
I think the druid of the claw is the best spell-casting unit in the entire night-elf arsenal. He is a very versatile unit and, as such, one of the best additions to any night-elf force. I recommend adding at least one druid of the claw to each group, and two or three would be better still. In his most basic form, he's a pretty decent melee unit against ground targets and buildings. Where the druid of the claw really shines, however, is in his spellcasting.
The roar special ability is an absolute must because it gives an immediate 25% damage bonus to all friendly units in the area. Having at least one druid of the claw in each group, then, can immediately make that group 25% more effective right off the bat. Further, because the druid of the claw also has the rejuvenation ability, which heals up to 400 HP over 12 seconds, having a couple of druids around can make the difference between a hero living or dying. They can also keep each other alive to cast roar again as needed.
As if this weren't enough, the druid of the claw has one final ace up his sleeve, namely, when his mana is exhausted or the front lines are threatening to break, the druid of the claw can transform himself into a bear. The transformation more than doubles his available HP, increases the amount of damage his attacks do, and tends to plug any holes in the front lines in a big hurry. Once the battle has slowed, the druid of the claw can always shift back to his night-elf form and recover mana more quickly. Until then, however, he's a big furry killing machine. That's flexibility.
The druid of the talon is the second-best spellcaster. His abilities are not always as simple to leverage as as the dryad's, but he can wreak havoc on an enemy with a little careful micromanagement. What the druid of the talon isn't is flexible. He is not a melee unit, having low hitpoints and doing little damage to targets on the ground. Unlike his clawed brother, he does have an air attack, but he still doesn't do that much damage to be effective. This unit is a rear-rank support unit, though his abilities can easily turn the tide of battle.
To be more specific, the faerie fire ability is one of his best. When set on auto-cast, a druid of the talon will use this ability liberally, reducing the armor of enemy units by five and making the unit visible no matter where it goes. This ability can make the difference between a huntress' third glaive hit doing no damage at all and harming a third enemy. It also tends to amplify damage done by archers by a nontrivial factor. In short, you should have at least one druid of the talon in any group of archers, auto-casting faerie fire at will.
Better still in combat is the druid of the talon's cyclone ability, which tosses any non-hero unit into the air and holds him there helplessly for thirty seconds. Alternately, this can be used to keep an enemy hero spinning wildly for five seconds. That's not nearly as long, of course, but five seconds can make a lot of difference, particularly if friendly heroes are busily doing their own thing. Cyclone does use up a lot of mana pretty quickly, so if you intend to use it be sure your druid isn't set to auto-cast faerie fire. When used properly, however, each druid of the claw can toss one or more units into the air, which can eliminate the threat from siege equipment in a big hurry.
Finally, if you need some quick reconnaissance and don't have the priestess of the moon handy, a druid of the talon can transform into a stone crow and fly over the battle field. While in stone crow form, the druid actually has more HP and regenerates mana more quickly than in his night-elf form. This makes it a very practical after-battle regeneration tactic that also allows gathering of additional intelligence. Like his clawed brother, then, the druid of the talon is pretty flexible. He's too fragile to put at the front lines, but he can sure help the fighters already there.
The hippogryph is the basic air unit of the night elves. They're pretty fast, pretty tough as air units go, and have a pretty good attack, though only against targets in the air. They make pretty good scouts, though such a purpose really doesn't make much sense in my estimation. Why use pricey hippogryphs for scouting when you can use the PotM's owl scout, the huntress' sentinel, the druid of the talon's stone crow, etc.? If scouting is what you need, the night elves have better tools available more cheaply.
Where the hippogryph is essential is in providing anti-air support. They're particularly handy to have around if the enemy is building the biggest, baddest air units available. Hippogryphs can also be used in hit-and-run raids against goblin zeppelins and other air units. Speaking generally, I'm not all that impressed with any of the air units in W3 because I think they're generally overpriced for as limited and fragile as they are. When you need anti-air capability, however, the hippogryphs are the clear favorite when playing the night elves.
What do you get when you combine two relatively fragile units into one? That's easy: you get an even more costly unit that does even less damage than it did before! Seriously, I don't know what Blizzard was thinking when they came up with the hippogryph rider. The hippogryph, as mentioned above, has no attack against targets on the ground, so I can understand the motivation to provide an air unit that does. Giving the hippogryph the ability to pick up and carry an archer is a clever and elegant solution to the problem. But why should the player have to pay such a ridiculous price in terms of damage output?
A normal hippogryph averages 42 damage against targets in the air with each attack. An archer averages 20.5 damage against any target. When you combine the two, the resulting unit does an average of 20.5 against any target. In other words, by spending all the resources necessary to combine two units into one, you get less than half the damage output against targets in the air. A player would be much better off keeping the two separate, using the hippogryphs against targets in the air and the archers against everything else.
This is the most dangerous time to be a night elf. The reason is that other races, most notably the orcs and humans, can pull off some really pathetic rushing tactics. For example, a popular orc trick is forward burrowing/towers. If the orc player goes for a war mill and an altar right from the outset, he can then summon a farseer hero very quickly. If done properly, the orc player can show up to the enemy base with the farseer and at least a peon or two about the time the enemy will have a small number of initial units, and quite likely no hero at all. The orc player then uses the hero to kill any resistance, often using the feral spirit and/or chain lightning abilities along the way, while the peons either build watch towers or burrows. The former will automatically destroy an enemy base and any units in pretty short order, while the latter will allow the orc player to blockade the enemy with a burrow full of orc peons.
There is very little a night elf player can do to fend off such tactics. In the startup phase, he simply won't have many ancients around to attack, and if he uses his tree of life, then he's essentially just lost the game because of the lengthy period it will take to re-entangle his gold mine. If you suspect the early rush, then your only hope is to build an altar right at the outset in the startup phase, even before you build an ancient of war. Your only hope against such a rushing attack lies either with the demon hunter and his mana burn or immolation abilities, or with the keeper of the grove and his powers. The PotM and archers just aren't going to cut it. Having said that, my default build order is as follows:
Whichever build plan you choose, you now have some leveling to do. If you've chosen the KotG hero, then you can start scouting and leveling him with only two archers, as long as you choose entangling roots or force of nature for his first special ability. Those abilities will allow him to divide and conquer when facing creeps. If you've chosen the demon hunter, however, then I don't advise leaving your base at all until he's backed up by at least three archers. I say this because it is utterly crucial that you don't lose even a single unit while leveling your hero. If you do, then you can pretty much count on losing in your first fight against another player.
At this point you have some choices. You should now be out of your base with a level two or three hero, and you will definitely need to micromanage your battles if you are to avoid losing archers. What you dare not neglect is further base building. If you want to live dangerously, then you can upgrade the tree of life to the tree of ages as a prelude for bringing in a second hero. I suggest first building a hunter's hall instead, however, to allow training huntress units and pursuing useful upgrades. Alternately, you can build a second ancient of war and try to overwhelm the enemy with lots and lots of archers. I very strongly advise against it, however, unless you know your opponent to be a bit slow. Archers are simply too fragile without a front line of melee units.
Bear in mind also that wisps are the only peon units in the game that have absolutely no ability to attack. Yes, they can commit suicide, but this only gets rid of mana and hurts summoned units; it doesn't do any conventional damage at all. As such, you're going to want to build at least one ancient protector as soon as possible. If you wish to delay this until the early phase of the game, that's often a good choice. Against a quick enemy, however, it can prove fatal, so judge wisely.
A couple of additional tips are also helpful. First, be sure to set all of your moon wells to heal automatically. The quickest way to do this is to ctrl+click a moon well, then right click the replenish mana and life option. If your game started at night, this will be particularly handy as the moon wells will replenish quickly. If at all possible, bring wounded units and your hero back to the moon wells during early leveling to heal and replenish. It really helps get the hero and his entourage back out and fighting creeps in order to level more quickly. Second, if at all possible, have a couple of wisps toward the front of your base harvesting lumber. In case the enemy comes to get you, you'll be able to grab one of them more easily in order to have it suicide, and that can easily turn the tide of battle when fighting summoned orc feral spirits or human water elementals.
What has been said already about individual units bears greatly upon one's choice of hero, and, more to the point, it essentially dictates which hero must first be chosen. Because the night-elf startup unit (i.e., the archer) is so weak compared to the startup units for the other races, it's essentially suicidal to choose the PotM as the first hero. For example, the humans can choose from a paladin, an archmage, or the mountain king. The paladin need only choose the holy light ability to heal 200 HP to a single friendly unit or do 100 HP damage to an enemy unit. The archmage can either summon a water elemental, which essentially provides another strong melee unit, or cast a blizzard that does a total of 180 HP damage across a nontrivial area. Finally, the mountain king can choose storm bolt and do 100 HP damage to a single enemy unit, or choose thunder clap and do 70 damage to all nearby units.
In contrast, what can the PotM do? Well, she can choose searing arrows and get a whopping +10 damage boost, or choose the trueshot aura and boost the ranged damage of those around her by 10%. For the record, since an archer does an average of 20.5 damage, that's a whopping +2 damage boost. Gee, it'll only take 50 shots to do the same damage as the mountain king's single throw. Needless to say, the PotM just doesn't cut the mustard as a good first choice.
The DH fares a bit better because of his powerful melee attack, and his mana burn or immolation aura abilities. Mana burn can be particularly helpful against an enemy wizard, but it doesn't do any damage or heal any friendly targets. As such, the DH and your own units are simply going to have to eat damage. The immolation aura does a better job at putting on the hurt, but it deals only ten damage per second at its lowest level. With that kind of burn, it will take forty-two seconds to kill a single human footman from the aura damage, and the DH will run out of mana long before that happens. Don't get me wrong; the DH is a decent first choice, but I think for most circumstances the night elves can do better.
In short, the KotG fares best thanks to his entangling roots and force of nature abilities. Personally, I suggest going the latter route, as I find it far more helpful in fighting creeps. The treants provide targets for creeps to attack first, and in many cases that means the creep-hunting party comes away entirely unscathed. Sure, it costs a few trees, but if that's the price, well, I say clear-cut that map! Of course, if you're going up against a small group with one really tough creep, the entangling roots spell can render that unit useless for quite a while while damaging him slightly in the process. Whether you select the DH or PotM next depends largely upon your overall strategy.
I should also note that it is terribly important to upgrade the night-elf heroes, particularly because their most powerful abilities are very useful. In the early game, things are a bit dicey for reasons I've already given. In the late game, however, the night-elf heroes can easily turn the tide of battle. The PotM's starfall ability, for example, is simply fabulous. It does a great deal of damage over a large area. Similarly, the KotG becomes still more important later because of his tranquility ability, which provides the fastest (i.e., 20 HP/sec) healing rate for friendly units across a large area. The DH's metamorphosis ability is also quite nice, but I don't think it's nearly as useful overall as the ultimate special abilities for the other two, though it does provide some nice eye candy (grin).