Howling Banshees have had it rough in 6th Edition. As a unit that always struck first and all carried power weapons, they were feared as one of the premiere assaults in 3rd, 4th, and 5th Edition. However, 6th Edition took away their ability to assault out of a transport and made their power swords AP3. The new codex has tried to improve them, but generally falls short.
Banshees went down in points cost while maintaining their statline and equipment, so that’s good. Their old Acrobatic rule has been changed so that they add 3” to their run rolls, making them quite fast on foot. Even so, it doesn’t help them when they charge and they’re not resilient enough to run across the table. Their masks have been altered so that they reduce any enemy unit in contact with a Banshee by 5 points of initiative. This has generally the same effect as their old I10 masks, but it does mean that they will strike simultaneously when charging enemies in cover, rather than first. If they had assault grenades, this wouldn’t be a problem.
The Howling Banshee Exarch is still pretty terrifying. She can take either the triskele (essentially a power sword that can fire 3 S3 AP3 shots at short range), mirror swords (a pair of master crafted power swords), or the much handier executioner, which gives them +2S and AP2. Of her exarch powers, I think only Disarming Strike is particularly useful as it allows here to take melee weapons away from her enemy in a challenge.
Overall, Banshees are still a frightening unit if they can reach assault, but they have problems crossing the table and assaulting into cover. As such, I don’t think they work very well in an aggressive role. However, they provide a very useful and affordable counter-assault unit for a defensive, shooty army. Their long run moves mean they should be able to reach any part of your line, and you should be able to keep them safe from enemy firepower until they are needed.
Striking Scorpions are in many ways the opposite of Howling Banshees. While Banshees are fragile but bring tremendous force to wipe their enemies out quickly, Scorpions are more resilient and rely on a large number of attacks to defeat their opponents. With a 3+ save, Scorpions can survive most protracted combats but their S4 chainswords aren’t nearly as dangerous as power swords. Striking Scorpions all come with mandiblasters, which automatically inflict a S3 hit on a single model in base contact. While this is a bit better than their old +1 attack, only models in base contact with the enemy get to use it, meaning positioning and charge distance become very important.
Striking Scorpions really pull ahead of Banshees when it comes to reaching the enemy. With Infiltrate and Move through Cover, Scorpions can deploy near the enemy and reach assault quickly. Stealth helps keep them safe on their approach, and they even have plasma grenades so that they can assault into cover.
The Striking Scorpion Exarch also provides a significant advantage. He can take chainsabres (a pair of rending chainswords with a shuriken catapult) or a biting blade (a +2S AP4 two-handed chainsword), but the real gem is the scorpion’s claw, a power fist that strikes at normal initiative and can be paired with another weapon for an extra attack. Even better, it also includes a shuriken catapult. That means that the exarch alone will deliver 4 S6, AP2 attacks at initiative 6 on the charge, enough to cripple most units. For Exarch powers, he can take Monster Hunter, Crushing Blow (for an extra point of strength), or Stalker, which allows him to re-roll to wound rolls in a challenge. All of these are useful, but none of them are necessary.
Striking Scorpions are an Eldar assault unit that can actually reach the enemy due to a combination of special rules and decent armor. They produce a fair amount of attacks in combat (roughly equivalent to veteran Space Marines), and their Exarch can tear apart most enemy squads. Add to this the fact that they cost relatively little compared to most useful assault units in the game, and Striking Scorpions are a great unit to add to your army. Whether you need a large squad to smash into the enemy army or a small squad to cause trouble and take out enemy scoring units, Striking Scorpions are a solid choice.
Fire Dragons are a controversial choice now. They were widely heralded as the best Eldar unit in the last codex, and most armies contained three squads of them. In the new codex, Fire Dragons received a substantial increase in their points cost but are still essentially the same unit. The only real change is that they now have a 3+ armor save, which is great considering the dangerous situations in which they usually find themselves.
Fire Dragons are all armed with fusion guns and meltabombs, making them possibly the best tank destroyers in the game. It doesn’t just apply to tanks; a unit armed exclusively with fusion guns will annihilate any targets they fire at except for horde infantry.
The Fire Dragon Exarch can either take the firepike (an 18” range fusion gun) or the dragon’s breath flamer (which, despite its awesome name, is just a heavy flamer). Either is useful, depending if you want to give the unit a bit of extra range or allow them to take on some infantry. They have access to the exarch powers Iron Resolve (+1 leadership), Crushing Blow (+1 strength), and Fast Shot (fires one extra shot when he shoots each weapon, but doesn’t affect template weapons). The first two aren’t much use, but Fast Shot is useful when paired with a firepike. I get the feeling the writers were grasping at straws when choosing the Fire Dragon Exarch powers, as only one really fits.
Despite their increased points cost, Fire Dragons are a supremely useful unit. They’re great at killing any hard targets and are a bit more durable than before. They’ll need a Wave Serpent to reach their target, but you’ll probably want to take extra Wave Serpents anyway. Honestly, they don’t even really need an Exarch; the basic squad carries enough killing power to take out most targets without him.
Harlequins are another Eldar assault unit, and have enough quirky rules to get them into combat. Their statline comes with excellent WS and I, as well as 2 attacks, and they come with Furious Charge and Hit and Run. They’re Fleet, but they are weirdly lacking Battle Focus. Anyway, they also ignore difficult terrain due to their flip belts and come with a 5+ invulnerable save. Even so, they wouldn’t be very good in assault without a harlequin’s kiss, a mandatory upgrade that gives them rending. Overall, that’s a fast but fragile assault unit, but it’s the characters that make Harlequin’s interesting.
The Troupe Master is a pretty standard upgrade character, simply bringing an extra attack along with a harlequin’s kiss or power weapon. The Death Jester is a bit more interesting because he carries a shrieker cannon, which is basically a shuriken cannon with Pinning. It doesn’t add anything to the squad’s assault ability, but it gives them some flexibility and it’s a cheap upgrade. Finally, the squad can take a Shadowseer, a level 1 psyker with Veil of Tears. This is an excellent power, as any unit that wishes to shoot the Harlequins must roll 2D6 x 2; if the Harlequins aren’t within that many inches, the unit doesn’t get to shoot at all. This means that the Harlequins are fairly safe from any shooting more than 14” from them (the test is only passed 42% of the time). This allows them to actually walk across the table with relative impunity. In addition, the Shadowseer gives the whole squad assault grenades.
Overall, the Harlequins haven’t changed much from last edition. They’re still a decent assault unit that can run right up to the enemy as long as luck is in their favor. As soon as someone gets within 8” of them with some bolters, they evaporate. The main change is that Veil of Tears has to be cast every turn now, so there’s a chance they won’t have it for a turn and be stranded without its protection. It’s not a large chance since the Shadowseer is LD9, but it can happen and will likely cost you the unit against an experienced opponent.