The archangel Radiant was created by the planeswalker Serra. Radiant and several thousand lesser angels lived in Serra's artificial plane where law, grace, duty, and reason were important. Serra had created her plane to be a place of beauty, purity, and hope.

Radiant did not like how Serra ruled—with a weak defensive army and Serra being treated like a god. Radiant wanted to rule the plane herself!

When Urza was rescued from Phyrexia, Serra took him to her plane and healed him. Five years later, Urza had healed, but the Phyrexians tracked him down to Serra's realm. The Phyrexians had brought an attack force to destroy Urza for foolishly entering Phyrexia. Serra was shocked as her white mana-based paradise was corrupted by the black mana-based Phyrexians. Radiant led an army to fight back the Phyrexians. Urza planeswalked back to Dominaria and Serra fled the plane. Hundreds of angels died that day and many more were taken as prisoners of war to Phyrexia. Radiant was free to rule Serra's plane.

Eight centuries later Urza had returned to Serra's realm. He was shocked to see that Radiant was killing her own people—believing they were Phyrexian sleeper agents (Phyrexians in human flesh who were unknowingly controlled by Phyrexia). However, Radiant was killing the innocent people as well as the sleeper agents. In truth, Radiant herself had unknowingly become controlled by the Phyrexians. Urza tried to convince Radiant not to kill her people, but she refused.

Urza returned with the flying ship Weatherlight to rescue as many citizens as possible. Radiant told her army that Urza had brought the dark ones and poisoned their paradise. He was their enemy here. The angels attacked Urza and his few defenses. Radiant finally came face-to-face with the planeswalker and ripped out the Thran crystals in his head. As Urza was about to die, Radiant tried to bring the two crystals together. The result was an explosion destroying Radiant and healing Urza. Urza collapsed the plane to get enough energy into a powerstone which allowed the Weatherlight to planeshift. Serra's realm collapsed.