The Terran race received some huge upgrades in StarCraft II, making it the most popular race to use in the months since the game came out. Fortunately, Protoss players have some recourse to fight off the powerful new Terran forces. In particular, the Protoss have several support units that, if used effectively, can easily turn the tide of battle in their favor. Some will be very familiar, but some bring all new abilities to the fore that completely change the way a game of StarCraft is played.
The most basic support unit for the Protoss to know is the observer. Anyone who played the first StarCraft will be no stranger to this unit. In StarCraft II, the observer looks the same and serves the same purposes as its predecessor. It is a very small cloaked unit that acts as a detector. It has no offensive capabilities, but is crucial to any game. Its cloak allows it to sneak into enemy bases undetected, if the opposition does not have detectors of their own out yet. Even then, the small size of the observer often causes enemies to overlook or miss its presence for long periods of time. The observer is a little more important in StarCraft II, because of the way high ground works. Units on the low ground cannot see units on the high ground unless the player has at least one unit on the high ground in that area. Observers can sneak onto the high ground to spot hidden siege tank threats, which can be deadly to Protoss ground attacks.
The high templar is also largely unchanged from the original unit in StarCraft. Psionic storm, which must be researched at the templar archives, decimates groups of Terran infantry units, which tends to be the backbone of most early and mid-game Terran attacks. It costs 75 energy, and works essentially in the same way as it did in StarCraft: target an area, and the psionic wave affects all units within that area. Feedback, which deals damage to a unit equal to how much energy that unit had at the time, is useful against powerful, specialized Terran units like the thor and the battlecruiser, a boon to the Protoss, as groups of these two units can annihilate anything very quickly. The high templar no longer has the hallucination ability, which is now found in the next, brand new unit.
The sentry is a small unit that is new in StarCraft II. They can be produced early in the game from a gateway after a cybernetics core has been built. The sentry has very little in the way of shields and hit points, so it is best to keep it behind the main lines of battle. It does do a little damage, at six points per second. It is most useful as a support unit. As mentioned above, it has the hallucination ability, which must be researched at the cybernetics core. Hallucination works a little differently in StarCraft II. Instead of selecting another unit out of which to create two hallucinations, the sentry automatically produces a certain number of hallucinations depending on which unit is desired. Any unit in the game can be used, even if the Protoss player has not teched up to that unit. For example, a sentry can create four fake probes, or one fake colossus. These hallucinations are weaker than regular units, cannot attack and are unmasked by detectors, but in a pinch can be used as good decoys for scouting or to absorb front line damage, especially from stationary fire from siege tanks. The sentry also has the guardian shield and force field abilities. The guardian shield is a small field that reduces the damage done by ranged attacks by two for every friendly unit within the field. Force fields serve as roadblocks that impede units’ movements. These are most useful for blocking off choke points in case of an attack, or for splitting up an enemy ground force to prevent reinforcements from reaching the front lines. Use caution, though; massive units like the thor can trample force fields in an instant.
Finally, there is the gargantuan Protoss mothership. The mothership is a unique unit in StarCraft II in that only one can be on the field at a time for the Protoss player. It is essentially an upgraded arbiter from the first StarCraft. Mass recall works in the exact same way; any friendly unit in a targeted area will be warped to the mothership’s location. The mothership also automatically cloaks everything friendly in a certain radius around it, but unlike the arbiter, the mothership can also cloak buildings. The last ability is vortex, which is a bit like the stasis field ability of the arbiter. What the ability does is different, but the effect remains the same. Every enemy unit in the targeted area will be sucked into a black hole, and stuck there, unable to attack, move or be selected for twenty seconds. This is very useful for holding off an overwhelming force of vikings until reinforcements can arrive; the mothership is very slow, and thus very vulnerable to anti-air units.