When did the WoL become the WoL?

[Kalise]

WoL became the WoL when we received Hydaelyn's Blessing after beating all the Primals and getting the crystals of light.

That is it. That is the point where we went from rando-adventurer (Blessed with the Echo) to the Warrior of Light (Or "Hydaelyn's Chosen")

Though, one could argue that after Ifrit we started on the path of being the WoL, due to us being tasked by Hydaelyn to go beat the other Primals in order to gain the crystals.

So is the WoL just a regular human, but, has juiced up crystal powers because of the Crystal of Light that you had? Or, does the WoL have innate special power that is simply augmented by the Crystal of light?

The WoL is something more than just a regular human (With the Echo)

Since, this is what Midgardsormr was testing for when he removed Hydaelyn's Blessing from us. He wanted to see whether we were worthy of the power. Thus, our strength of will and well physical capabilities were put to the test. Then we kicked the butt of an Ascian and were deemed worthy.

Thus we then regained the Blessing and were once again amp'd by the crystals.

It's also noted that during the final scene with the Warriors of Darkness, they all had crystals too (Including Urianger...) which were all used to go speak with Hydaelyn/Minfilia.