Several instigators were sealed with the bulk of the purifiers on Cybros. When Artanis came to Cybros to reactivate the purifiers, instigators took part in cleansing the platform of the zerg present.
The instigator only appears in "Purification" where it joins several other purifier forces in attacking the zerg as the player activates the purifiers from stasis.
Compared to the normal stalker, the instigator has identical stats, but its Blink ability functions differently. The instigator stores Blink charges every four seconds, to a maximum of three. When the instigator Blinks, it consumes a Blink charge, but Blink has no cooldown. This effectively allows the instigator to Blink multiple times in succession, and to Blink more frequently than the stalker since its charges replenish faster than the stalker's cooldown for Blink.
The instigator teleports a short distance away. Blinking consumes a Blink charge. One Blink charge is generated every four seconds, to a maximum of three charges.
- The instigator is the only faction-specific variant of a unit that is not accessible to the player. The adept serves as the purifier faction option for ranged attackers, and the instigator does not appear in any subsequent missions to feature purifier armies after "Purification"; they instead use adepts. Data in the map editor suggests that the instigator may have been intended to fill the adept's role and was replaced later in development.
- On the Blizzard store page for the Fenix Co-Op commander, one of the images shows an instigator next to various other Purifier Units. However, the instigator is not one of the units available to the commander.