Wait, how did Nasus know Xerath's name?
Azir and Xerath knew a slave with name would mean death punishment, so they made a deal and used this name only among themselves. How did Nasus even know? Did this rule change after Azir as being emperor? And Nasus couldn't learn it after Fall of Shurima either since Azir was dead and Xerath was imprisoned. There are many ways to close this plot though. Like Azir removes this rule as emperor or Xerath says his name in fight of Shurima's Fall. Wish we had what really happened in Fall of Shurima in detail.