Protoss

Overview

The Protoss were the first race created by the Xel'Naga. As the Protoss grew, they expanded rapidly in their knowledge and technology. They worshiped the Xel'Naga at first but eventually they rebelled against them. The Protoss live in a tribal society. They have powerful psionic capabilities that are even more personified by the tentacles that come out of the back of their heads. There was a minority in their race called the Dark Templar who had different philosophies than what the other Protoss followed, the Khala. They were banished from the Protoss home world Aiur and they cut off their Tentacles making them impossible to detect in the depths of space even telepathically. This also made them able to learn different technologies.

Protoss Units

Starcraft
Probe First used in places where it was to dangerous to have actual workers. They are used for harvesting Minerals and Vespene gas. They can also warp in buildings. But unlike the Terran SCV, they can leave to other activities once a warp has been initiated.
Zealot The most common Protoss unit. They wear advanced cybernetic suits that allow them to project a psionic shield around their bodies and create powerful large energy blades.
Dragoon Protoss warriors who have been severely wounded or crippled can volunteer to become anew inside a Dragoon exoskeleton. They are able to fire anti-particle spheres that are very destructive. They can attack both ground and air units making them a vital creature in every Protoss army.
High Templar The High Templar are veterans of the Protoss army. They have walked the path of the Khala and were successful in ending the maddening rage of the Zealot. They instead focus their power on Psionic abilities such as the Psionic Storm which attacks all units in a targeted area ad they also have the ability to create a double of a unit. This confuses the enemy and buys you time when overwhelmed.
Dark Templar These are Protoss who were banished from Auir. While being in the deep space for generations, they have learned the secrets of space and are able to bend light around themselves rendering them completely invisible They also have powerful psi-blade weapon technology. Dark Templars no longer merge to make Dark Archons but rather just Archons in Starcraft 2.
Archon These powerful creatures are born when two High Templar fuse together. This is only done during desperate times and the Templars who do this are honored in scriptures forever. They sacrifice their physical form and become being of pure energy and rage. The can attack both ground and air units. In Starcraft 2, Archons can be formed with the fusion of any protoss in the Templar class.
Dark Archon The Dark Templar have had to face many harsh environments and they have had to adapt and transform their bodies to survive. The Dark Archon is one of the results of that. They are formed when two Dark Templars fuse together. The Dark Templar has some interesting abilities and has no physical attack of it's own. One of them is "Feedback", this ability turns the energies of the unit against themselves causing immense damage. Another ability is "Mind Control" allowing any unit to automatically come under their control permanently. Finally, "maelstrom" is an ability that allows the Dark Archon to stun all units within a targeted area. In Starcraft 2, Archons can be formed with the fusion of any Protoss in the Templar class.
Shuttle Similar to the Terran Dropship, the Shuttle allows for the transportation of units to anywhere you want. They have no pilots and are almost fully automated.
Reaver The Reaver is a Protoss war machine. They have a tiny manufacturing plant inside and produce explosive robotic creatures called "Scarabs". They do explosive damage to buildings and ground units.
Observer These are small drones that are used to record battles for the Protoss archive. They are completely cloaked and give off very little to no energy. They are very useful in spying on the enemy as well. This unit also makes a return in Starcraft 2.
Scout These are used for exploration and as the name suggests, scouting. They are also pretty powerful. They have both air to air missiles as well as ground attacks. They are also very fast. This makes them very effective units. A weakness to this unit has be it's cost of production is high.
Corsair These ships were built by the Dark Templar to safeguard their fleets. They use neutron flares as it's attack. It also has an interesting ability. It uses to Pilots psi-energy to create the "Disruption Web" to stop any attacks from buildings or units on the ground but does not effect air units.
Arbiter The Arbiter is a powerful component to the Protoss army. It is loaded with psychic Judicator crews. They use their energies to project an energy field that renders all units around the Arbiter to be completely invisible, except it doesn't work on the Arbiter itself. It has the ability to transport any group of units to wherever the Arbiter is located. It also has the ability to create a stasis field around a unit making it unable to move or attack and it last for a long time.
Carrier One of the most powerful units in the Protoss army. They act as both command centers and weapons for war. While it has no attack of it's own, it produces small robotic crafts knows as "Interceptors" They relentlessly attack anything with much force. Each carrier can control a maximum of 8 and are deadly when used in larger groups. They do return in classic form in Starcraft 2.

Starcraft II
Immortal After the shrines where Dragoons were created became infested with the Zerg, the protoss decided to create a new weapon where fallen veteran Zealots could still service the Protoss. The Immortal is a Dragoon replacement that has the ability to shield itself from large massive weapon fire but not smaller weapons fire. It is a valuable weapon against more powerful units.
Stalker The Stalker is a war machine built by the Dark Templar to survive in hostile environments. Using their knowledge of the dark void of space, they have built these machines with the ability to "blink" or teleport a shot distance making them very difficult targets to hit.
Warp Prism After years of studying space and time, the Protoss have discovered a way to create a crystal computer that is able to transport units to wherever the Phase Prism is located as well powering units and buildings, acting like a portable Pylon, which is as a structural energy source used to power Protoss buildings.
Phoenix A new Protoss aircraft that replaces the old Scout and Corsair. It's only ability now is that is picks units up off the ground and encases them in a bubble allowing other phoenix aircraft to shoot them while making the unit helpless.
Colossus This towering robotic machine uses it's long legs to walk up and or down cliffs giving it an advantage over units that would have to use a ramp to get down. It has powerful thermal lasers on each side of it's body and focuses the beams on a single unit. Effective on small light units like marines or zerglings.
Void Ray These flying Protoss vehicles were created by a combined effort with the Dark Templar after many years of prejudice. This combination led to the creation of this machine. It uses a single prismatic core that fires a powerful beam which gains strength over time when fired on a single target. This may not seem effective at first but once used in large numbers, it can destroy larger more powerful units and or buildings in seconds.
Mothership The most powerful unit in the Protoss arsenal. Not only does it have it's own ability to attack with homing Psi-energy blasts, it also has some very interesting abilities. It has the ability to make any unit it around it to become completely invisible. It does have the ability to create black holes which would suck in and remove units from the game for a period of time thus making a much larger force very weak. You could say it's a giant Arbiter.

Protoss Heroes

Adun

When a select tribe of the Protoss decided to go against the ideas of the other tribes of Protoss, the templar, led by Adun, were ordered to kill them. Adun decided to try to hide them from the other Protoss to save them from being slaughtered. Eventually the leaders of the Protoss found out that these tribes still exsisted. A battle erupted and at the end Adun sacrificed himself to allow the rogue tribe to escape. The tribe eventually became know as the Dark Templar. Adun's actions are remembered by all Protoss through the saying "En Taro Adun" (In honor of Adun).

Tassadar

Tassadar was one of the first Protoss to discover the Zerg. After learning about the Zerg, the Protoss leaders ordered Tassadar to purge any world the Zerg infested of all life. When the Zerg invaded Terran world's Tassadar attempted to destroy the Zerg without harming the Terran. The Protoss leaders were enraged by this and ordered him to return to Aiur. Tassadar refused to return and eventually found the Dark Templar. Because he spent time with them he was considered a traitor. After Auir was invaded they renounced their claims that he was a traitor. During a battle on Aiur Tassadar combined his templar energies with the energies of the Dark Templar and crashed his ship into the Zerg Overmind, killing himself and the Overmind. Shortly after his sacrifice many Protoss began using the saying "En Taro Tassadar" (In honor of Tassadar).