Everything in this article is my opinion unless otherwise stated. As a progamer for several years now, I have a wealth of personal experience and observations to draw upon. That said, sometimes I have to speculate.
The adept is a gateway unit that only requires a cybernetics core to produce. The adept is a tanky frontline unit that excels vs light units due to its bonus damage. The bonus damage is substantial so the adept is poor against armored units such as marauders, roaches, and stalkers. Also, adepts 2 shots all workers making them an excellent harass unit. The twilight council has an upgrade which increases the adept’s shields by 50 raising its total life from 180 to 230. As shields often stay unupgraded gaining 50 shields with minimal armor is less impactful than a 50 hp increase.
The adept is really interesting because of Psionic Transfer. Psionic Transfer creates an image that moves about the speed of a reaper and can be controlled. This image cannot attack. After 7 seconds the adept then teleports to the image. This image is not affected by any collision from units although it cannot pass through buildings. The adept’s controller may cancel the image to prevent the teleportation. This allows the adept to threaten multiple locations at the same time. The most common use for this is to send the adept to one mineral line and images to the other thus making it very difficult for the defender to accurately split their army. The adept opens up a new range of harassment opportunities for protoss as well as new compositions due to its high hit points.
By the numbers:
Damage: 10 (+13 vs light)
Build time same as a zealot
Movement speed: same as a marine
Psionic Transfer: Projects an invulnerable Psionic Image that can move but cannot attack. After 7 seconds, the Adept teleports to the Image's location. Adept can cancel the shade ability at any time. When you cancel, the shade disappears and you don’t teleport. The image is about as fast as a reaper.
Shield upgrade, costs 100/100 researches from twilight council, gives adept +50 shields bringing them to 140/90.
Adepts rule the early game vs Terran. They 2 shot marines and so do an even better job of maintaining early map control compared to stalkers. In addition, Psionic Transfer gives them opportunities to bypass an early bunker and trade for scvs or force a fight vs marines. Protoss also has a much easier time scouting as the image created gives them vision. Terran must wall off their main and raise depots if any images are attempting to sneak into the main. Adepts are excellent at getting into position while there is other action on the map as the default configuration for Terran will be to have the wall open. Adepts excel in small unit encounters and are able to overcome the healing of medivacs on marines without much trouble due to their high burst damage vs light.
Adepts can close the gap against ranged units instantly using their image and also cut off retreat.
There are a number of strong adept openings, allins and timings early on although their effectiveness in a head on fight falls off greatly as soon as marauders, stim, shields, and medivacs are out. Shields allows marines to survive 2 shots from adepts, although it depends on the upgrades and if they’re able to heal at all after stimming before taking damage.
Nightend uses his adepts to completely surround the terran forces.
Due to adept’s relative low range and lack of anti-air, bio + medivacs are able to kite an adept heavy army and pick up if things get too dicey. Adepts are generally supplemented with blink stalkers to limit medivac movement and immortals to help deal with a heavy marauder based composition. Late game, adepts are used mostly to harass. Warp prisms and image runbys are very common in high level TvP and force Terran to have heavy map control or take huge losses when they move out.
Due to adept’s high hitpoints and mobility, both players open 2 gate adept almost every game. As adepts do bonus damage to other adepts, the best unit to counter early adepts are also adepts.
Adepts from both sides scout using their image.
Stalkers, zealots and sentries just don’t do enough damage early game to stop adepts from trading for probes early on. Currently PvP involves a lot of adepts roaming the map and using the image to get into their opponent’s base. As adepts 2 shot probes, 2 adepts are able to do a lot of economic damage unless the defender has a significant number of units already in position.
Adepts use their image to peek inside his opponent’s base.
Adepts see their opponent out of position and transfer into the base where they wreak havoc.
Adepts bounce from one mineral line to another harassing workers while his opponent tries to keep up
Adepts work great in a warp prism as they two shot workers.
Some protoss players have taken to setting up the top of their ramp so they can wall it off with a single pylon to keep adepts out of their base as needed. Stargate has relatively limited usage here due to the threat of being overrun by adepts but can be effective in catching your opponent off guard or out of position.
A typical adept vs adept fight looks a bit like roach vs roach, but there’s far greater opportunities to sneak by and gain position.
The natural transitions once players make it up to 2 base lie in either robotics or twilight. Robotics provides a measure of safety against dark templar while also giving access to Disruptors.
As archons do bonus damage to adepts and do not take extra damage, they can be a potent mid game response.
Immortals and colossus see little play in the matchup currently as immortal’s bonus damage is irrelevant with adepts forming the majority of each player’s army and their shield spell having too long of a cooldown to use them for soaking a lot of damage. As adepts move relatively slowly and are pretty small, disruptors are generally able to catch a significant number of them in the blast.
Disruptors also do excellent damage as adepts tend to clump and are slow.
Players also choose to go into blink and/or the adept shield upgrade for either timings or general pressure. While this leaves them a bit more vulnerable to dts, twilight allows the core army to be significantly stronger.
Adepts largely fill the role of zealots in this matchup. They are strong against zerglings, have high hitpoints and relatively low range. Since they do not do bonus damage vs roaches, they do not perform well and can have trouble actually getting in range to deal damage to the hydralisks. Psionic Transfer helps a lot with positioning but it can be difficult to get the adepts in position without isolating them completely from your army when trying to get on top of the hydralisks. Early game, adept timings largely take the place of zealot timings as adepts are a bit easier to micro and are much more versatile. Psionic Transfer allows them to place additional pressure on the zerg as well as bypass walls while also being an extremely effective scout. As the game goes on, adepts won’t necessarily form a core part of the army as they often do in the other matchups but generally get at least sprinkled in due to their high hitpoints, ability to clear zerglings and scout.
Nightend uses adepts to attack one mineral line while his images allow him to quickly move to another.
Adepts move in to pressure the 3rd and punish the zerg for being out of position when the transfer to their image in the natural.
The adepts stutter step away from zerglings and then cast their image backwards providing an escape if the zerg continues to chase.
When fighting against protoss, it’s important to get an idea of how many adepts to expect so that you can prepare in time. Once the harass starts, it becomes very hard to stabilize, but setting up ahead of time makes a huge difference toward defending. Walls are incredibly important for defense. As the protoss player can always cancel the teleport, adepts near your base offer a near endless and risk-free way to scout. Pushing adepts away from your base will be necessary to deny vision of your tech path. In low numbers, adepts will beat most units, especially once they have the shield upgrade from the twilight council. Be wary of leaving your base with minimal map control as you may be inviting a large number of adepts to invade and give you nightmares. The adept succeeds at being useful and creating new ways for protoss to control the map, scout and harass but is a little too similar to the zealot in terms of what units it’s good/bad against. While there are a number of situations that the adept is better than the zealot in, the reverse is less true. The zealot fills few roles that aren’t already filled by the adept. So, while the adept is creating new and interesting interactions in all three matchups, it is largely doing so at the expense of the zealot.
Thanks to NighEnD for providing replays and protoss insight.