Author notes: This is a story that I've been thinking about for some time. I've read a few crossovers of Familiar of Zero and Starcraft involving the zerg and the terrans but nothing about the protoss. So I decided to try if I could make it work. This is my first story here in so if you have any pointers or criticism you're more than invited to say it.

Disclaimer: I don't own Starcraft nor Familiar of Zero

Prologue: Cold is the Void.

A bright flash of green and red erupted from the blades of two protoss warriors, illuminating the darkened room with the physical manifestation of their will. One of the Khalai and the other of the Nerazim. Two factions that were once sworn enemies until the first great war known as the Brood War. It brought both tragedy and unity to the protoss race, placing eons of hatred, spite and strife aside in order to face a common foe and help each other to prevent the extinction of the firstborns.

These two warriors engaged in combat were two of the most important figures among their brethren. The one wielding a green warp blade and embraced in shadows was named Zeratul, a Dark Templar. His nerve cords were cut short, as the teachings of his people demanded in order to maintain a connection to the Void and its power. The other protoss was Artanis, the Hierarch to his people yet he struggled with the weight that came with the responsibility of leading his brethren during this dark times that brought the emerging of the creators of his species. He, like most who followed the faith of the Khala, had his nerve cords coiled into a long braid letting him listen to the emotions and thoughts of other Khalai and allowing them to do the same to him.

Recently, Zeratul had finished collecting fragments of an ancient prophecy depicting the demise of all life in the universe at the hands of Amon, the last of the xel'naga. With this discovery, he went to warn the terran commander and friend Jim Raynor about the bleak consequences of killing the Queen of Blades. It changed the terran's mind and pushed him to de-infest the aforementioned foe, reverting her back into Sarah Kerrigan. A terran ghost operative with unprecedented psionic power once betrayed by her superiors that caused her to become a genocidal and cunning being bent on vengeance.

It was after Kerrigan escaped the Dominion's forces that she received a visit from Zeratul inside a massive cruiser-like zerg creature, Leviathan, she was using as a base of operations. He guided her to the birth world of the zerg, Zerus and told her how to become more powerful than she ever was in her previous infested self, free from any outside control, using her drive for vengeance to get her to comply.

And then, Zeratul returned to his brethren, if only for a short time. He warned them to not try to invade Aiur, the End war was coming and it could become the end of everything and everybody if it wasn't dealt with accordingly. He was marked as a traitor, with not unfounded reason. He, after all, killed the previous Matriarch of the Nerazim during the Brood War to release her from mental control. But they only knew the what, not the why.

Now, it came to this.

Zeratul had been right. Amon corrupted the Khala by his will. Using the nerve cords as a conduit to his control, he turned protoss against protoss, Khalai against Nerazim. It was shortly after finding Artanis in the middle of the battle against the zerg occupying the planet and the corrupted protoss warriors adding even more chaos to the mayhem that was the invasion when the Dark Prelate saw the Hierarch struggling to get free from the grasp of the Fallen One's will. But he finally succumbed to the crushing volition of Amon.

A crackle of red lightning and a shockwave erupting from Artanis began the battle, with it, a veil of smoke shrouded Zeratul as he vanished from sight only to appear a few meters away, warp blade ignited. The only way to free the possessed protoss was to sever his nerve cords, but it proved to not be an easy feat as Artanis charged at the Dark Templar. He kept dodging the relentless slashes until he jumped over the Hierarch, the tip of his blade barely brushing against the nerve cord. Just as he landed, he was grabbed by his neck and brought close to his opponent.

"This body, all protoss, are mine." Said the voice of Amon from his puppet. He then proceeded to throw Zeratul to a wall nearby and electrocute him with crimson lighting, using it to drag him to the floor. As tiny shocks of energy arced around his prone body, he heard the Dark One speak again. "I will shatter this corrupt cycle… you shall not stand against me."

Unsteadily and slowly, Zeratul rose and ignited his green warp blade once more as he vowed "My life for Aiur."

The possessed warrior answered his words by powering both of his psi blades with the corrupt crimson energy of Amon. They both charged for one last time. A brief, yet bright, flash of light was the final strike for both warriors as after a few seconds one of them fell to his knees and the other turned to acknowledge it. Just as his head turned, the action made the results visible as the long coil of nerves fell to the floor, one of its ends still smoking.

Instantly, Artanis cried out to the heavens as violent bolts of red lighting erupted from within him to the darkened sky with a force that briefly lifted him from the ground. Just as it ended, he dropped down to his hands and knees as he panted tiredly from the mental strain the mind control had on him. His dazed gaze fell upon the kneeling shape of his friend. His wounds too grave for him to do anything more than to say:

"The keystone… will guide you… to the xel'naga…"

Zeratul finally collapsed unceremoniously as Artanis approached slowly. The weight of his actions felt heavier than anything he could have ever imagined. He gently held the body by the shoulders and turned the face to him as he said his last words to his longtime friend as he followed the same fate of the protoss upon death, leaving only dust in the wind, a cloth that he used to cover his face and his trusty warp blade.

"Zeratul… forgive me."

"Awaken, old friend."

A pair of brilliant green lights shone through the deep sea of emptiness. The sudden inhale of nothing that followed made the only being floating in the void known to apparently no one. Dazedly, he swiveled his head from left to right trying to find the origin of the voice. A voice he thought he would never hear again ever since his brief visit to Aiur during his search for the prophecy of the end of everything.

"Tassadar? …Is that you?" Asked Zeratul into the space before him. He knew his days were counted ever since he stepped into the doomed invasion for the recovery of the protoss home planet. He didn't expect to become part of the void, or stay conscious after his demise.

"It seems you have set the events to prevent the end of everything in motion. Just as it was planned." The ghostly visage of the protoss hero appeared in front of the Dark Templar. Zeratul looked mesmerized as his Tassadar continued. "Do not misunderstand. You did fall in battle, but I need you to accomplish one more task for the sake of the universe."

"What do you mean, Tassadar?" Floating closer to the apparition, the Dark Templar tried to find the words to express his confusion. "I have done everything I could to prevent the end. What else is there to do?"

"Worry not, Zeratul. I am sure your sacrifice will bear better results than you would ever expect. But the place of your task is in another reality altogether." He paused. Clasping his hands before him, Tassadar created a ball of light that soon developed into a mechanical object which he instantly recognized.

"A probe…" Curiously, he took the golden worker in his hands. Looking at it in its frontal lens, he notice something was amiss. "It is deactivated." Raising his head to Tassadar, he said, "This other reality, it is in danger, is it not?"

Nodding, the ghost explained. "Indeed. And the only one able to save everyone is in need of guidance. The power she wields is beyond her comprehension and it may cause her to tread an uncertain path."

"And you want me to become her guide." Zeratul deduced. "I admit the suddenness of this request is disconcerting, but if it is for the greater good, I shall accept this role."

"Thank you, Zeratul. But in order to avoid… troubling inconveniences, you must be concealed during one day. The probe shall do the rest."

"I will not disappoint you, old friend." After a few seconds, he finally asked. "How am I to know who is my charge?"

"Do not worry, you will know when the time comes."