Ok so to clean up this whole thing, I read over the posts here and put together an awesome graph (mad MS Paint skillz yo) that kinda sums up everything that makes you a Warrior of Light.



So what we are left with is that a Warrior of Light is any person tasked by Hydaelyn to stop bad crap from happening. Warriors of Light appear at any time in the story, but NPCs refer to the ones from before the calamity (legacy) because they do not know that you (non-legacy) as a player are one as well (they don't know you were contacted by Hydaelyn, your story has just started). Basically everyone playing are warriors of light since everyone is aiming for the same goal. It is only at the end you are called a Warrior of Light even if you're non-legacy because, by then, the NPCs have acknowledged the divine path and power you have been granted, you are "joining" the ranks of the warriors from 1.0.