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Guardian Shield is a defensive spell cast by the Protoss Sentry. It creates a shield bubble around the Sentry that reduces the damage of all incoming ranged attacks by 2. Guardian Shield lasts for 15 seconds and only affects friendly units. Friendly buildings are not affected by it.
Guardian Shield is a support spell used against armies with a primary focus on ranged attacks.
Guardian Shield is the most useful against large numbers of ranged troops that deal smaller amounts of damage and against rapidly firing ranged units. Against larger damage dealing ranged units, Guardian shield, although still useful, is less effective. This means Guardian Shield does not scale well with total ranged damage received as the game progresses.
The Guardian Shield also underlines "attribute counters" which focus on building units that are not vulnerable to the opponent's primary bonus damage. E.g. a Guardian shield only chops 10% off a Marauder's attack against the shields of one of your Stalkers. But if said Marauder has to deal with a Zealot or an Archon, the 2-damage-reduction equals 20%. This can be further improved with a head start on defensive upgrades.
The Guardian Shield only covers an area with a radius of 4 while the Sentry itself has an attack range of 5. In order to cover friendly melee units such as Zealots, the Sentry should be micro'ed closer to the skirmish.
Guardian Shield significantly reduces the damage received from Sentries and Void Rays due to the high attack speed of these units. Although a Carrier's Interceptors may not shoot often individually, their combined amount of very small attacks is an excellent application for the Guardian Shield. One should also not forget the application often seen of this ability in early-mid game PvP pushes. It greatly reduces the damage of Stalkers, Immortals, and Sentries, which are all staples of an early PvP defense.
Guardian Shield is very useful against Terran armies as they are primarily composed of ranged attack units. This is especially the case against common Terran armies of Marines/Marauders/Medivacs. In a major engagement with Marines/Marauders/Medivacs it may become necessary to activate multiple guardian shields in quick succession as the casting sentries are often picked off quickly.
The Sentry's Guardian Shield can be the difference maker in any encounter against a Mutalisk, Roach, or Hydralisk based army. With the Protoss units already being more durable than most Zerg units, the additional defensive boost can help counteract the massive numbers of a Zerg army.
In Combination with Other Spells
When used with the Sentry's other spell, the Force Field, a well microed Protoss army can divide its opponent's forces while sustaining heavy amounts of ranged fire. This sort of play allows the Protoss player to dictate how battles will be resolved to a higher degree, all while having a slight ease of mind knowing that the Guardian Shield will support their troops for a brief period of time.
- Shields friendly units only
- Effects do not stack
- Does not shield friendly ground units on different cliff levels
- Does shield friendly air units as long as their projected position is inside the 4 radius - consider it to be a cylinder rather than a sphere, as the graphic effect suggests
- Does not shield buildings
- As of Patch 1.4.0, all non-melee attacks are being reduced - except for the Planetary Fortress'. It is likely to have been missed and should be considered a bug
- If a unit has a melee animation (such as the Roach and Hydralisk), Guardian Shield does NOT reduce the damage done when the melee animation is used.