What is a Warrior of Light?

[DPZ2]

At first, you have the NPCs who are using it in the early story to refer to the adventurers blessed with the Echo who stood beside Louisoix at the Battle of Cartenau and were sent into the interdimensional rift. When people try to recall them, they cannot. They liken it to trying to make out their silhouette against a blinding light - ergo, the Warriors of Light.

Aaaaaand the last vision of a certain religious personage suddenly makes sense..