Yeah it’s def Eonar given she was the one who took Ysera and made her into a Dragon Aspect from a Protodragon and empowered her and gave her the charge. Ysera is materially Eonar’s “pet”, Eonar’s experiment, of Eonar’s power.
Maybe it’s a still-unseen member of the Life Pantheon, but doubt it.
It’s probably Eonar.
Disappointing maybe, but it’s probably her.
Definitely not Elune as she’s probably going to be elevated to the rank of First One, lest the Night Elf playerbase burn Blizz HQ to the ground.