Ensouled Darkness
In the darkness of the caves it waited, alone. Its hulking body, once so terrifying and deadly, now trembled beneath a layer of rust and rot, while its optical lasers cut desperately through the darkness in search of... what? Something. Anything. It couldn't remember how long it had been since last it had received a message from the creator, since last an order gave purpose to its death-filled existance. A century, perhaps, maybe longer. Too long, at any rate, for now it was useless, driven beyond sanity by the decades of isolation. And yet... and yet it still hadn't surrendered the last vestiges of hope. Still it searched for a meaning, striving for some final quest so that it might find glorious death.
Searching all frequencies... filtering distortion... negative contacts.
Nothing. It was still alone, caught in the darkness without purpose. The creator, thrice accursed Yawgmoth, had vanished, taking its controllers with him into whatever hell he had earned, and had left naught but an empty void within its cybernetic mind. Truly, it was alone and, for the first time in its immeasurable existence, it was afraid. How could it continue to exist, alone in the darkness of this hateful world? It couldn't. No, if the aven didn't tear it apart, the elves would annihilate it with their vile living mana, corrupting its perfect balance of mechanoid and living flesh and making it like them; impure, pathetic.
It couldn't allow that. No, it couldn't allow itself to become such a failure. Its lord may have abandoned it to its terrible fate, but it had not abandoned Yawgmoth's dream. It was Phyrexian, a perfect blend of unblemished metal carapace and masterful human mind. It wouldn't allow itself to fall to their level; not while it could still serve the lord, not while it could still fight.
A ground shaking crunch marked its first step, a tangible tremor the next, and then it was in motion, lumbering toward the exit and shedding flecks of rust as dark mana from the foulest death pits of Rath surged into its ancient weapons. Surely there would be a village at hand; a place to cleanse of the Dominarian taint. Even if there wasn't, it would not rest. No, not till death claimed its mind and rust shattered its body. It was Phyrexian; it would offer no peace.