Invaders are fully automated drones used to bolster allied units on the battlefield with an arsenal of psionically based technology. To distinguish themselves from their counterparts, these robots use Dark Templar colors for their armor and have a scorpion-like tail armed with auxillary psionic crystals for more power (Starcraft II Development: Sentry/Development).
While keeping most of the Sentry's force field emitting technology, Invaders combine it with parts copied from Arbiters. Instead of creating an energy field that lets anything under it escape, the reinforced projections temporarily ENTOMB targets in a hardened space-time globe. The modified force fields could be used to block resources from being mined. This effectively hinders enemies from producing more advanced forces (Starcraft II Development: Oracle/Development)
One of the main reasons why the Protoss lost the first war was their disadvantage in numbers. With the loss of their homeworld, Protoss now rely more heavily on support from robotics and powerful psionics. To compensate for this, Sentries utilize holographic technology to cast the illusion of greater numbers to confuse enemy forces and draw fire with Hallucinations. Invaders combine advanced neural interface technology with holograms to create psionic projections dubbed FIGMENTS on the battlefield. While hallucinations cannot do any real damage to enemies, Figments cause neural feedback to whatever they are attacking. Victims preceive themselves taking actual damage until the feedback eventually overwhelms them to the point of dying (Marvel: Psionic Blasts; New Line Cinema: A Nightmare on Elm Street).
Though Guardian Shields are great for reducing small arms damage, they lack the strength to handle heavier artillery strikes and more exotic weaponry. To rectify this weakness, Invaders utilize experimental LEECH BARRIERS when supporting allies during sieges. Composed of both psionic and void energies, Leech barriers not only reduce offensive forces, they store it for later use as cycling sparks (Beast Machines: Optimus Primal). This cycling of excess energy reinforces Leech barrier stability until it reaches critical and discharges a psionic shockwave knocking back anything near it (Legend of Zelda - Ocarina of Time: Din's Fire; Halo - Reach: Armor Lock; Mass Effect: Tech Armor). While enemies are stunned by the shockwave, allied forces have enough time to either attack or retreat from them. Leech barriers can even absorb special weapons such as psionic storms with minimum damage. In any siege operations, a single Invader can make a large difference in the size of both allies and enemy forces.
- ENTOMB - creates an invincible "globe" over a small area that blocks the movement of ground units. Units caught under the shield when it is placed are trapped; while under the field they cannot attack and cannot be attacked. Spell lasts for 15 seconds
- FIGMENT - Invaders produce false copies of units to distract and attack enemy forces. Duplicates have the same amount of HPs as the originals but take double damage with attacks half as strong. Number of Figments depends on unit cost (see Hallucination)
- LEECH BARRIER - create an aura which reduces incoming ranged damage to allied units by 4 and negates special weapons such as psionic storms. Once barrier life expires, it lets out a psionic shockwave that knocks away nearby units and stuns them momentarily