Calamity Trigger

The Successor of the Azure is the title of those who inherited the Azure.

Information
The Successor can observe the world as the Eye of the Azure and is the one who can find the Amaterasu Unit.

Noel Vermillion became the main factor to break the loop of time after inheriting the Azure. Nu -No.13-, after the process of assimilation between her and Noel, became another Successor and became able to summon the Master Unit.

Noel was in fact the Master Unit all along and the Original Prime Field while Mu-12 was just a body she used until they separated. Noel's true body was inside the Master Unit acting as it's core, but left due to the pressure of everyone's desires.