Adepts were deployed during the End War, when groups of Templar volunteered to adopt Purifier ordnance refined by Phase-smithKarax. This ordnance allowed the Templar to amplify their psionic potential and project their minds for teleportation while weakening their enemies. Adept ordnance would continue to be used by the Daelaam, but never could reach the optimal performance of Karax's original prototypes.
In a short amount of time, the psionic amplification techniques of the adept were reverse engineered by the Tal'darim, and incorporated into their arsenal, equipped on their most promising warriors.
After the End War, cultural trends hearkening back to the Golden Age of Expansion within the Templar Caste led some adepts to wear ceremonial armor from the era.
The adept is a slow-moving core gateway unit with a ground-only ranged attack and normal movement speed. This unit utilizes its psionic transfer ability to teleport to nearby locations. It is designed for harassment. This is especially true against enemy resource lines, especially in the early game, where the adept can bypass base defenses. Adepts do well when paired with zealots, as both have a similar resource cost. The zealot is more durable, while the adept has a stronger ranged attack, especially against light units.
It is intended that the adept serve as a core unit option in mid/late game, taking on roles once held by the zealot and stalker, and in some cases, doing better. Its psionic transfer ability is distinct from the stalker's blink ability, in that blink is more focused on twitch-based micro, while psionic transfer is based on the timing and positioning of the teleport. The adept can be controlled independently from the copy it generates. Use of the psionic shade can help the adept retreat, but if executing a "move" order, the adept will automatically stop to use the shade. Thus, the "move" order will have to be executed again if the adept is to keep retreating.
Projects an invulnerable psionic image that can move but not attack. After 7 seconds, the adept teleports to the image’s location. The shade may be canceled at any time, and the adept won't teleport. The shade has a sight radius of 2.
In the Legacy of the Void campaign, the adept is one of three variants of the ranged warrior unit that the player can choose in the war council, the other two being dragoon and stalker. It's the only biological unit of that role, and the only biological unit of the Purifier faction.
The adept has higher hit points, move speed, attack damage and range, and resource cost, but lower attack speed, than its multiplayer equivalent. Its attack can also hit air units. Enemies touched by psionic transfer would temporarily take more damage from attacks.
Fenix can build adepts in Co-op Missions. These adepts are mechanical, and can summon shades that attack as well. Fenix can download the Talis champion into one of his adepts, increasing its stats and giving it a bouncing auto attack if researched. Fenix's adepts can attack air and ground units.
Adepts can be utilized by Amon's forces. Their stats are identical to their campaign counterpart, and can also attack both air and ground units.
The following section contains information from a previous version of StarCraft II which is no longer valid.
The adept was a protoss unit in early builds of StarCraft II, as part of the team's effort to revise the base units for each race. It was a ranged attacker, but was cut during development for being too similar to the marine, and because it was decided that the basic units for the first game.
During the Legacy of the Void beta, adepts had an upgrade which gave their attack bounce damage. It was removed as it wasn't generating the "micro interactions" Blizzard was hoping for.
It received a buff to its health as it was weaker in gameplay than the developers had anticipated.
Blizzard has considered allowing an option to trigger when the adept teleports per its psionic transfer ability. However, they feel that doing so will make it too similar to the stalker's blink ability.