Vivien Reid arrives in New Capenna because its mixture of industry and surviving nature feels wrong. Tezzeret leads her below Caldaia, where passage through the Planar Bridge has torn organic material from a wounded Phyrexian. The creature is Urabrask, praetor of the Quiet Furnace and an enemy of the orthodoxy now uniting New Phyrexia under Elesh Norn.
Urabrask does not reject Phyrexia itself. He rejects compulsory unity. Norn intends to make every world Phyrexian and every Phyrexian obedient to her vision; Urabrask believes transformation without choice is domination. That distinction does not make him safe, and Vivien never treats him as such. It does create a temporary alignment between people who understand that Norn's victory would erase every independent form of life.
Halo helps Urabrask repair the damage inflicted by interplanar travel. Vivien gathers information and learns that the Adversary destabilizing the families is Ob Nixilis, while Tezzeret continues serving interests he only partly reveals. Urabrask wants Elspeth because her history, spark and capacity to inspire Mirrans could make her the symbol around which resistance forms. Vivien insists that Elspeth must be informed rather than compelled.
The alliance is built on converging goals, not trust. Vivien approaches Elspeth only after confirming that the knight is pursuing the same threat and allows her to continue searching the Maestros' archives. Urabrask agrees to wait, but his patience has an edge: the city is already close to breaking, and a crisis may force Elspeth to choose the rebellion before she would choose it freely.