After the Brothers’ War, Urza devoted millennia to understanding and defeating Phyrexia. He created Karn as a silver golem able to travel through time, established the Tolarian Academy and supported generations of research. Catastrophic experiments showed that preparing for one disaster could create others, yet he continued to treat scale as an argument for secrecy.
The Legacy was less a conventional weapon than a system of interdependent parts. Artifacts gathered across different ages, the Weatherlight itself, Karn and the engineered heritage that produced Gerrard were meant to converge at the right moment. Dividing the design protected it from capture, but it also kept participants from understanding what had been made of their lives.
Urza’s foresight mattered. Without long preparation, Dominaria would have faced Yawgmoth with no answer capable of reaching him. The same preparation revealed his central failure: he could imagine centuries of mechanics more easily than the autonomy of people expected to complete them.