Storm guards are cyborg soldiers carrying Hell-Fire Submachine Gun's and using energy shields that make them more difficult to damage from the front.
Appearance: Cyborg wearing green metal full body armor and Cylon-style helmet, with a wrist-mounted energy shield.
Primary Weapon: Hell-Fire Submachine Gun (Incendiary Bullets: 4.5% damage) (Flamethrower: 12.5% damage) Other Attacks: Melee Strike (65% damage) Special Ability: Energy shield
Storm Guards are the most commonly encountered Special Guards you'll face in the game, in fact you'll see them being mass-produced on an assembly line in Level 17: Sabotage. They typically appear in pairs, often fighting alongside standard Krone Guards. Storm Guards are equipped with a circular wrist-mounted energy shield that protects them from all projectile attacks. The shield is indestructible, and will completely neutralize all projectiles that hit it. The shield is large, and leaves almost no part of the Storm Guard's upper body exposed (although it is possible to target a Storm Guard's legs, doing so isn't easy when they're running around and shooting back at you).
Storm Guards are equipped with Hell-Fire submachine guns, making them incredibly deadly at close-to-medium range. They can mow you down in a couple seconds with their high rate of fire, or at close range use the Hell-Fire's flamethrower secondary fire to burn you down even more quickly. Storm Guards are also well armored, and can survive more than twice as much damage as a standard Krone Guard soldier.
Storm Guards first appear about halfway through the game, in Level 13: Forced Entry. They appear fairly often; you'll fight them throughout 5 of the game's levels, and a total of 28 of them appear throughout the game.
Equipped with a large energy shield in one hand and a Hell-Fire submachine gun in the other, Storm Guards pretty much charge at you while blasting at you with their Hell-Fires, relying on their handheld energy shields to protect them from your return fire. Unlike Flash Guards or Warp Guards, they move normally, and can't run at super-speeds or teleport. Still, their protective energy shields and Hell-Fire weapons make them considerably more dangerous than standard enemy soldiers.
The Storm Guard's major weakness is the Time Stop ability; while in Time Stop, their energy shield vanishes (apparently it fluctuates on a frequency or some technobabble like that), allowing you to target them directly. A good strategy is to use Time Stop to neutralize their shield, then shoot them with the ThunderBolt crossbow for a one-hit kill. You can also shoot them in the head with any weapon, since a single headshot will kill a Storm Guard outright.
The Storm Guard's shield also doesn't protect against explosive splash damage, so you can take them out with explosive weapons. This makes the E.M.F. Cannon effective against Storm Guards, since the energy rifle projectiles explode on impact (several standard shots or a single powerful charged shot should splatter a shielded Storm Guard). You can also blow up Storm Guards with the Bloodhound rocket launcher, or blast them with the Surge Gun's secondary fire beam. Two direct hits on a Storm Guard's shield with the ThunderBolt crossbow should also kill them.
You can drop a Storm Guard to it's knees by shooting it in the legs with automatic weapons fire, but doing so doesn't really help you much since they just get back up again after a second and resume shooting you up.
Finally, you can use Time Slow to slow Storm Guards down, allowing you to snipe their exposed feet with your ThunderBolt crossbow.
Their Hell-Fire submachine guns make Storm Guards extremely dangerous at close range, so no matter how you fight them, you'll want to keep as far away as possible from them.