Urza Planeswalker is a fictional character from the universe of The Gathering, best known for his millennia-long struggle with Yawgmoth and the plane of Phyrexia.
Over their years at Tocasia's camp, Urza and Mishra made several important inventions and discoveries. While the most obvious of these was the ornithopter, the most important turned out to be the Caves of Koilos. A mysterious cave filled with old Thran artifacts, the Caves were also the location of a long-sealed gateway to Phyrexia, used in every Phyrexian infiltration and invasion of Dominaria. On their first visit, Urza and Mishra acquired the Mightstone and the Weakstone respectively, the two halves of the stone that had been holding the portal shut. Mutual desire for the other brother's stone led to a falling-out between Urza and Mishra, as well as the inadvertent death of Tocasia.
Urza settles back to ground zero, and finds Tawnos, his apprentice, sealed in a mechanical coffin that somehow kept him safe throughout the maelstrom. They both have a short reunion, and Tawnos goes off to tell Urza's wife, Kayla bin-Kroog, that Urza had died with Kayla's name on his lip. Kayla, knowing Urza through and through, would rather believe that he had died with Mishra's name on his lip, instead. She spends the her remaining mortal days with her blinded son, Harbin, and writes the Antiquities War, a book that would become a very important source of history for Dominarians.
Urza wanders Dominaria for a time, and finds another planeswalker, Meshuvel, who educates him in the ways of his kind. Their relationship doesn't last, however, as Meshuvel attempted to trap Urza, as she "fears" looking at Urza's eyes. Urza, after his ascension as planeswalker, found that his Mightstone and Mishra's Weakstone, has imbedded themselves in his skull, and together with the sylex blast, have helped him become a planeswalker. Urza, at this time, has also developed many derangements, one of which is a fixation to destroy the Phyrexians as it had destroyed his brother.
Urza journeys Dominaria for a few years more, where in every city all he can hear are curses against the Brothers and their War. Urza has also taken up wandering the planes, where in one plane, he finds Xantcha, a Phyrexian newt (a human-looking sleeper agent) who was deemed "defective" by the Phyrexians and left for dead. Urza heals her, and though Xantcha tells him honestly that she is Phyrexian, Urza simply ignores the admission and thinks she was the victim of Phyrexian torture and brainwash.
Urza then makes a travelling companion of Xantcha for a short while, and shows her the dragon engine that he plans to use in his conquest and destruction of Phyrexia. Xantcha tells him that what he has is extremely insufficient, but Urza doesn't listen, and proceeds to raid Phyrexia with his dragon engine.
Xantcha unknowingly hitches a ride in the dragon engine and uses Urza's raid as a chance to get her "heart" back from the keepers. According to stories circulated in Phyrexia, a Phyrexian newt's heart is said to be the repository of a newt's mistakes--whenever a newt commits a mistake, the Ineffeble one, Yawgmoth, the lord of Phyrexia, makes a scar mark on their hearts. Too many mistakes and the heart is destroyed, and its owner with it. Xantcha doesn't know if the legends are true, but she's afraid nonetheless, and acts to save her heart while Urza lays siege on Phyrexia.
Urza and his battered dragon engine successfully punch through three layers of Phyrexia's nine, but while at the fourth level (where Xantcha was), Yawgmoth, the sleeping lord of Phyrexia, suddenly invades Urza's mind, and incapacitates him. Xantcha climbs onto the dragon engine, and forces Urza to remember where he was, and forces him to planeswalk them out of Phyrexia.
Once outside Phyrexia, in a strange plane, Xantcha told Urza to burn Yawgmoth's name out of his mind, which Urza literally does. Urza and Xantcha spends the next few months dodging Phyrexian hunters as they planeswalk from plane to plane. Eventually, on an icy plane when Urza almost experienced defeat, he managed to planeswalk to Serra's realm, an artificial plane populated by warrior angels created by the planeswalker Serra. It is there that Urza spends months being healed by the benevolont planeswalker before moving on to exploring the other planes for hundreds of years with Xantcha.
Ratepe was a young Dominarian recruited by Xantcha, Urza's Phyrexian assistant. Xantcha sought out Ratepe from a small nation in order to impersonate Mishra, Urza's long dead brother. Urza was becoming increasingly obsessed and guilt ridden over his role in his brother's death. So much so that he was abandoning his defense of Dominarian in the hopes of finding a way to undo his brother's death. Xantcha brought Ratepe, posing as Mishra, to Urza in the hopes of alleviating some of his guilt and allowing him to focus on defeating the Phyrexians. Thanks to Xantcha's coaching and Ratepe's ability to hear Urza's Weakstone singing to him, Ratepe was able to help shock Urza out of his guilt. He continued to help Urza and eventually became Xantcha's lover. Both Ratepe and Xantcha were killed when Urza fought the Phyrexian Demon Gix in Koilos. Ratepe and Xancha's sacrifice helped Urza defeat Gix and also revealed to him the shared Phyrexian ancestory with the Thran.
By implanting Xantcha's heartstone (her only remains) into a silver golem, Urza created Karn, a being that could theoretically enter rifts created by his temporal disruptor and change the past. Tragically, during the machine's trial run, the temporal vortex drew far too much energy and "exploded", destroying the majority of the Tolarian Academy, killing inhabitants, and covering the island in odd (and sometimes horrific) temporal disturbances. Although Karn and Urza survived without injury, and much was learned about the history of the enemy, Urza was devastated.
After being distraught and guilt-ridden over causing another horrible explosion (the first being the Sylex), Urza eventually rebuilt the Academy and realized that the temporal rifts throughout Tolaria could be used to his advantage. He engineered magical-technological armor that allowed Tolarian researchers to finish decades of work in mere hours in fast-time bubbles. Potions derived from water in slow-time bubbles could extend a promising student's life by years. For the first time, Urza had a viable means for gaining ground on the multi-millenial head start the Phyrexian invasion force had so long held.
Urza blamed himself for the horrid results of his actions against Phyrexia. To amend his actions, Urza prepared an invasion into The Gathering)'s Realm. He undertook this effort to remove a quickly growing Phyrexian power he had lead there, which ran unquestioned in the absence of Serra herself. Knowing he himself could not stop the now already large force that was being built, the 'walker prepared a large force and a vessel to carry it across planes. To build this vessel, Urza required specific wood. Yavimaya, a very old forest, held this wood. Urza, in his visit to request the wood, was captured by the forest spirit Multani to pay for the destruction of Argoth. After a four year imprisonment, Urza was released and with his reprieve, granted the wood he needed to make the planeswalking vessel, The Weatherlight.
With this vessel Urza attacked Serra's Realm, using a united force of many different artifacts. After defeating the Phyrexian force, and saving many refugees, Urza let Serra's Realm destroy itself, as all artificial planes do without the guidance of a Planeswalker.
With his victory, Urza thought himself forgiven in the many places he had brought trouble. He had done two great deeds, defeating the infestation in Serra's Realm, and the creation of unity between war torn races. Also, with a vessel that could travel planes, Urza could amend many of his other faults on other planes.
Urza constructed an army of sorcery and power to resist the coming invasion. He called them the Metathran. He also began a project of massive scale which he called the Legacy. The centerpiece of this was the ship Weatherlight, commanded by none other than Gerrard Capashen, the end product of a long line of genetic experiments. Gerrard was the most important piece to the Legacy, and was Urza's greatest achievement. Along with the ship's crew, Gerrard began his quest to assemble the rest of the Legacy before the plane had completely become overrun.
The invasion was here, and nothing short of the completed Legacy weapon would end it.
During the invasion of Dominaria Urza gathered the nine Titan Engines together with their planewalker operators and launched a counteroffensive against Phyrexia. Their goal was to destroy the heartstones which kept most of the Phyrexians alive. One of the planeswalkers, Tevesh Szat, betrayed the nine and killed Daria. Urza's response to the betrayal, which he expected, was to seal Tevesh Szat's soul within a soul bomb that he created. Similar to nuclear weapons, these soul bombs were the most destructive force yet to exist within the Magic universe.
Years of fighting the Phyrexians had left Urza cold, and more than a little mentally unstable. In an oddly Nietzschian way Urza had come to love and respect the Phyrexians as perfect creatures, even as he fought against them. Barrin realized this, before his death, and tried convince Urza to pull away from madness. Barrin did not succeed.
While in his counter-invasion of Phyrexia, Urza was approached by several angel-like Phyrexians and was convinced to betray his Planeswalker ally, Taysir. He triggered the same part of Taysir's suit, the "kill rubrik", that he used to kill Tevesh Szat. He was led to the seventh sphere, where he was presented with his brother, who had been tortured in this clockwork hell for thousands of years. He then proceeded to the final layer of Phyrexia to worship Yawgmoth, where he was joined by Gerrard.