"I am a light that is not a candle but still must be lit."
This refers to the Winged Light itself. Unlike the main currency of regular candles, you must physically light the Winged Light statues in Eden to offer your light to them.
"I grant wings to those who have lost all their own."
This describes the ultimate function of the light sacrificed in Eden. The Winged Light given to the statues grants you Ascended Candles. You use these special candles to buy Wing Buffs from the main spirits, which are permanent Winged Light that you receive upon rebirth. So, by losing your temporary wings (Winged Light), you gain permanent ones (Wing Buffs).
"I am found in the ruins of the past, where the storm never ends."
This points directly to the location: the Eye of Eden. This is the seventh and final realm, an area of crumbling ruins constantly battered by a devastating storm of rocks and darkness.
"Though I bring hope, reaching me is a final, terrifying descent."
This speaks to the emotional experience of the Eye of Eden. While the journey results in rebirth and hope (the ability to continue playing and grow stronger), the act of traveling through the Storm and giving up your light is an emotional, often scary, descent into the darkness where your character ultimately "falls."