Storm Guardians are the more choppy version of the regular Eldar Guardians. Despite the precious and fragile nature of Eldar life, sometimes the brutal economy of war requires Autarchs to commit troops to shock assaults and bloody close combats. You would think that the Howling Banshees and Striking Scorpions would have done that job instead, but sometimes your only option is to throw bodies at a problem till the problem goes away. I guess the Eldar really do run on a budget.
Though rare among the Eldar warhosts, the Storm Guardians are warriors ideally (read barely) suited to the reckless maelstrom of melee. Armed with Shuriken Pistols and crystal-toothed Chainswords, they wade into the press of enemy ranks, hewing open flesh in vivid sprays of gore. However, unlike the clumsy butchery of the other races of the galaxy, there is a beautiful violence to the way the Storm Guardians dispatch their foes; resembling more like ballerinas that can cut your head off.
Elegantly balanced Chainblades carve bloody figure-eights in the air as they find the throats of enemies, the Storm Guardians are one agile motherfuckers like their kin, ducking and diving through the foe's errant fire whilst shooting their Shuriken Pistols point-blank into their ranks. Storm Guardian squads are a pretty rare sight thanks in no part with their ever dwindling population and the Eldar's need for self-preservation on not getting too close into melee....which is than 'conveniently' rendered moot with the common frequency of Howling Banshees and Striking Scorpions. Nonetheless, they remain effective, acting as assault troops in support of the Craftworld's Aspect Warriors.
Although they lack the protection afforded by Aspect Armour, they still fight like juiced up figure skaters on cocaine. Combined this with the common lethality of their weapons and you will see them dicing the enemies of the Spess Elfs into minced dog food. Storm Guardian squads invariably need to move fast, sprinting from one hotly contested strongpoint to another, and thus they forego the use of heavy weapon platforms. Instead, these darting fighters bear specialist weapons; they often bolster their short-ranged firepower with Fusion Guns and Flamers, and some even wield Eldar Power Swords, allowing Storm Guardian squads to excel in a wide variety of close assault roles.
On the Tabletop
In 8th edition, there's one word that can describe Storm Guardians: Pitiful. In prior editions, Storm Guardians had an ever-so slight edge against most other armies' equivalents due to their higher initiative, letting them strike first against most enemies. Even though initiative has been removed, Storm Guardians received not a single perk to compensate. With only a single attack at a measly S3, the only opponents Storm Guardians can reliably kill in melee would be fellow GEQ infantry, though without psychic support (which would be far better served on more premium melee units, like Howling Banshees), they're still only wounding those guardsmen on 4's. Being a heavily melee focused unit, this is a crippling flaw that hampers their effectiveness severely. Life isn't complete shit for S. Guardians though, for they do have a precious few things going for them:
9th edition did no favors for Storm Guardians. Though an MSU squad isn't as vulnerable to blast weaponry as their defender kin, a single grenade can still easily wipe out half a Storm Guardian squad. Though the nerf to overwatch does help them actually make it into combat, they'll still do virtually nothing to anything in a fistfight. Their low volume of attacks, pitiful strength, lack of AP, and virtual absence of ranged presence pretty much regulates them to simply distracting an enemy unit long enough for one of your actually competent units to come in and clean up whatever's left (of your Storm Guardians). The ability to take up to two fusion guns/flamers does give them enough offensive presence that your opponent can't simply dismiss them out of hand, but you should never expect them to prioritize them over the rest of your army willingly.
- Low Cost: For Craftworlders, Storm Guardians are the single cheapest troop choice available to you, at 48 points for a bare-bones squad of eight dudes as opposed to the 60 points for a squad of five Rangers/Dire Avengers. So, if you're looking for absolute, pure volume of dudes, Storm Guardians can fill that role. They can even have a max squad size of 24, the highest of any single infantry squad you can field.
- Assault Weapons: Storm Guardians are the only non-aspect infantry choices that can take Fusion Guns or Flamers, making them the cheapest way to field said guns. While you won't get as many fusion guns as a squad of Fire Dragons would, you do have more in-squad meat shield protection to keep those special weapons around. Plus, with their pitiful range and melee focus, Storm Guardians will be one of the precious few units that actually benefits from 8th Edition's Battle Focus!
...and that's really it.
- Shuriken Pistol: The only ranged option for most of your dudes, this fires a single S4 shot at 12", with a chance of AP-3 on a roll of 6. While Guardian Defenders can fire off twice the number of shots per dude, at least your S. Guardians can pop off their pistols in melee, so there's that going for them I guess.
- Aeldari Blade: The basic-bitch butter knife the S. Guardians brought with them from their day jobs that they use to lightly wipe the sweat off of their enemies' foreheads. Don't worry though, if they miss with their attacks, these let them re-roll failed hits.
- Chainsword: Probably the only acceptable weapon, the Chainsword doubles the number of melee attacks made with this weapon. This is statistically better than re-rolling misses, and since it's a free upgrade, there's no reason not to take it.
And 2 out of every 8 Guardians can take one of these Special Weapons:
- Flamer: Likely the standard choice, Flamers actually work quite well on Storm Guardians given the ranges they'll often find themselves in. These may spike the cost of your Guardians by 9 points a pop, but they're arguably worth it.
- Fusion Gun: While these will give your S. Guardians a surprising amount of bite, giving these guns to them will all but guarantee that this squad won't last past turn 3. Mixing one into a maximum sized group can definitely help deal with the odd monster or vehicle, though there are much more attractive options to deal with those in your other slots.