Prologue
One thousand and ninety-seven years ago a baby was born from the dying trunk of the oldest tree in the center of a dying grove.
Heimdall was the first to know of her, and instantly sent the King and Queen of Asgard to the child's aid. They arrived at the grove on the Plains of Ida, and followed the lonesome cries until they found her in the hollow of the trunk.
Queen Frigga swept the child into her arms, and soothed her crying, and King Odin imparted the first gift the baby would receive. He named her Idunn, the Rejuvenating One, for the grove in which they found her had sprung to life at her birth, and now bore fruit. The couple agreed that they would raise the baby as their own, as their two sons' sister.
Yet when the three reached the edge of the trees, the trees' branches grew thick and thorny, and would not allow them to pass. The grove was the baby's mother, and even the King and Queen of Asgard could not separate Idunn from it. Frigga and Odin had no choice but to place the baby back into the hollow where she had been found. The grove's thorns withdrew themselves.
The child grew up in the grove, with frequent visits from Frigga and her two sons. She was born during the age of travels to Midgard, and her childhood was livened with tales of the others' adventures in it.
Idunn loved Midgard so much, that when she outgrew her tree hollow, Thor made her a house like the ones the Viking mortals lived in in the center of the grove, just next to the Mother Tree.
Idunn was beloved by all who met her. The only weapon she wielded was kindness, a staff made from the Mother Tree, and the poisonous herbs and bark of which only she held knowledge, but the people of Asgard had never had the displeasure of knowing her staff or poison.
Idunn grew up lonesome. She knew trees and herbs and the animals that made the plains and grove their home, but she did not know of people. Frigga visited often, but only for hours at a time. Thor came when he could, but it was rare, and Loki was no longer welcome.
There were no friends for Idunn, only the stories and songs she told herself while tending the apples she grew.
One day, after a year or more of absence, Thor knocked upon Idunn's door. He came from Midgard, where he'd fought Ultron, alongside of heroes such as Iron Man and Black Widow and Captain America. He came to ask a favor.
Midgard was in need of a guardian.
