Eonar's power made Ysera an aspect, through Freya as a conduit who asked for it. Eonar has never met Ysera, so being her "Pet" doesn't make sense.
Considering that when Ysera dies, it is Elune who yanks her soul out and sends her on her way, it's safe to say that that "god" is the sister of the other nature god who deals with souls.
But I could be wrong, Blizzard has made things obvious before and then did something completely stupid with it later(they forget)
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Girl goes to pet store, wants to get this puppy. Calls mom up and says "Hey can you buy this for me?" Mom gives her the Credit info and indirectly pays for it. Girl who doesn't live with parents, brings it to her boyfriends house and barely plays with it, boyfriend falls in love with puppy, trains it and spends almost every day with it. 10 years later, dog dies and the boyfriend is the one to bury it.
That's basically the real life similarity to Eonar, Freya Elune and Ysera.