The Protoss bore silent witness to the portentous arrival of Humanity to their edge of space. Although the Protoss were uncertain of the vagabond origins of the Terrans, they knew that these volatile, short lived humans would prove to be interesting study. Two centuries passed as the Protoss watched over the budding Terran colonists. The Terrans had succeeded in building up rudimentary colonies on over a dozen worlds within the Protoss? borders. Although the technology of the Terrans was inferior to that of the Protoss, they adapted to the worlds upon which they lived and thrived. The Protoss found the Terrans to be fascinating in that they constantly fought against one another, yet still flourished and advanced their technologies and industries by leaps and bounds.

The Protoss were alarmed at how quickly the Terrans were to access and drain the natural resources from their various worlds. It seemed to the Protoss that the Terrans had no respect for the delicate balance of nature, as they recklessly sped from one world to the next, leaving nothing but barren wastelands in their wake. Bidden by the strict dictates of the Dae?Uhl, the Protoss were forbidden to directly interfere with the reckless Terrans, no matter how much they wished to do so. This disjointed relationship lasted for many years between the two races. Yet a routine Protoss scouting mission found evidence that spelled certain doom for the hapless Terrans.

The High Templar Tassadar accompanied by his renowned Templar expeditionary force, found a number of small biological constructs floating near the borders of Protoss space. Upon close inspection, Tassadar deduced that the rather nondescript alien organisms were in fact deep space probes. Although Tassadar could not discern their point of origin, it was clear that they were heading towards the Koprulu sector of Terran colonies.

Tassadar brought the living probes back to Aiur for immediate study. The strange aliens were unlike anything that the Protoss had ever seen before. The respective phsiologies of the probes were apparently engineered for deep space travel and reconnaissance. In an attempt to discern their primary quarry, the Protoss focused the energies of the Khaydarin Crystals through the tiny minds of the probes. The Protoss were shocked to discover that the alien probes responded quickly and naturally to the powerful energies of the Crystals. Their shock was garnered from the fact that only creatures born of the Xel?Naga?s proto-genetics could properly process the energies of the great Crystals. More alarming was the vague thought stream that kept repeating, over and over, through the tiny brains of the probes; Find Humanity,Eradicate,Learn,Evolve!

The Protoss speculated that the probes were the harbingers of a bold new threat to their section of the galaxy. If the creatures were engineered with Xel?Naga technologies, they would be very advanced and extremely powerful. It seemed clear to the Protoss that this new race constituted a palpable danger to all living beings, and that wherever the greater bulk of the race was, it must still be searching for the unsuspecting colonists.

The Protoss began to send out advance scouts to scour the surrounding space-ways for any sign of the alien invaders. Tassadar claimed that under the dictates of the Dae?Uhl, it was the chosen responsibility of the Protoss to protect the races under their watch. The Conclave, however, argued that if the ?worthless? race of Terrans had already been infested by some new threat, they must be put to the flame and eradicated. A great debate began between the Judicators and the Templar as to how they should involve themselves in the Terrans? imminent plight.

The one fact that both castes agreed upon was that the creatures were undeniably engineered through Xel?Naga sciences. And if they were indeed created by the Ancient Ones, the Protoss had best be on their guard. It was agreed to send Tassadar and his expeditionary force to monitor the Terran worlds and attempt to discern the severity of the impending danger. To this end, Tassadar led his command ship, the Gantrithor, and an escort of massive Protoss warships towards the Terran sector of Koprulu.