The epilogue segment is very, very interesting to me, because I get such strong vibes of it being directed specifically at Louisouix.

"Thy Life is a riddle, to bear rapture and sorrow.
To listen, to suffer, to entrust unto tomorrow.
In one fleeting moment, from the Land doth life flow.
Yet in one fleeting moment, for anew it doth grow.
In that same fleeting moment,
Thou must live
Die
And know."

But, examining it as if it was talking to the primals, doesn't this seem to hint at the theory that's been floating around that the Ascian summoning methods are somehow corrupting the Primals or bringing about incomplete versions of themselves? Much like a riddle, we really know nothing about the Primals' origins or motivations. They are forced to listen to the suffering of their people, and bring them hope, but being incomplete they must drain the very land they seek to save of aether.

They take life from the land, yet that act in itself brings about life. (Perhaps hinting that bleeding the land of Aether will give rise to Zodiark?)

...I'll admit I'm at a loss for Live Die and Know for Primals, though. Perhaps in death, they return in some way to their true nature, untainted by Ascian summoning, and know.... something we don't yet. This feels like a bit of a stretch to me though.