Disclaimer- I don't own Magic: The Gathering.
Lifeblood of the world.
Red, color of blood and fire, mountain and earth. Color of fury and rage and passion.
Green, color of flora and fauna, nature and forest. Color of growth and life and renewal.
White, color of purity and heaven, plains and fields. Color of healing and light and wrath.
Blue, color of water and ice, sea and sky. Color of manipulation and trickery and deceit.
Black, color of dark and hell, swamp and decay. Color of greed and malice and death.
Mages affiliated themselves with different colors according to their natures and birthplaces. Those of the plains thrived with white mana, those of the sea loosed their blue mana, and so on, and so forth.
Urza Planeswalker, as was his right as a 'Walker, could use each and every color of Magic. And yet he was unique among all magic users, for he affiliated himself with no color.
Every other planeswalker, despite their ability to tap into all magic, still flocked to their natural colors. Those who had lived their mortal lives as sailors clung to blue mana, those who had known greed and death delved into black magic, those who were full of fury and hate burned with red, those of growth and life held fast to green mana, and the righteous stuck to the power of white magic.
But not Urza.
He wasn't into growing things, or manipulation, or healing, or anger, or death. He cared nothing for any color of magic, drawing upon them for aid, nothing more.
Not even blue mana, the magic many believed Urza held favor for, was close enough for him to identify with.
There was no part of this world that Urza Planewalker could hold affinity for.
Where another planeswalker walked among fields of wheat or soared in the sky or ambled around forests, Urza tinkered in his labs, among machines and metal. Where any other mage felt affinity for sea or swamp, plains or forest or mountain, Urza loved the artifact, the intricacy of it, the almost otherwordly quality of it.
Barrin once commented that Urza seemed more Phyrexian, constructing artifacts instead of wielding magic, always questing for perfection, never satisfied with what came before, what already exists. He struggled for the compleat, as the Phyrexians named it.
In reply, Urza merely noted that one fights fire with fire.
Barely audible, the Master Mage had remarked that fire burns the body, while Phyrexia corrupts the soul.
The planeswalker had nothing to say to that, merely continuing to work on his machines.
No, Urza Planeswalker cared not for this world, only for his machines, his metals, and his vengeance against Phyrexia.
He was neither red nor white nor green nor blue nor black.
He was a shade of gray.