why during cutscene its always like this ... (small spoiler)

[KyahAlmasy]

The aetheric lightsword/beam wasn't even the Echo or Blessing's doing, but an abundant source of aether you had at the time. You defeated Nabriales using Tupsimati and Igeyorhm with Nidhogg's eye.

Yes the Aetheric sword we used on Lahabrea was due to the echo. The ones we create with the Eye, and Tupsimati are pale imitations of the one Hyd gives us, and aren't nearly as strong either. When we attack Nabriales she even says "Recall the time you struck down Lahabrea with the blade of light" Another example of how much more powerful we become with the power of light, than on our own. Hyd can literally create a blade of light for us without any tools and gather the Aether sufficient enough for our cause. This is why the Ascians are frightened of us. Not because I'm a White Mage, or Ast, but due to the power of light bestowed upon me.

Other scenarios such as void ark, praetorium, and I believe Ramuh references the Warriors of Light, as well as you bringing in a party of elite adventurerers/sell swords.

As Krile has explained to us, there are lots of different warriors of light. Heck, anyone with the posession of the echo is considered a warrior of light, but this is not the same as the Warrior of Light we play. You can tell even when you first encounter the derplander and he says "So you are the warrior of light, savior etc" I doubt he's running around saying that to every single Warrior of light he runs into. While there are many different incarnations of the warriors of light, like Krile, they all have their own role. But in accordance to the canon of our individual story, we are the only warrior of light capable of the feats we see in the game.