The Arrayed

ljósálfar or " Light Elves" reside in one of the more dominant planets within the Nine Realms, called Alfheim.
Alfheim was ruled by a Vanir by the name of Freyr.
Freyr is the god of sunshine and rain, and is also the patron of bountiful harvests. He is a God of peace and a brave warrior, and an honorary member of the Aesir despite having first arrived on Asgard as a hostage.
Freyr wishes to keep peace and good tidings between his home Alfheim and Asgard. It was agreed between the two kings that once Freyr's eldest daughter (from his elven marriage, naught from his twin sister of Vanaheim) became of age, she was to wed a Prince of Asgard. The Prince that would not become king of his homeland Asgard, would become betrothed to the Princess of Alfheim and in time would become King and husband to Freyr's heir ... Arraya.
This story takes place after it had been announced that Odin proclaims Thor to become his successor and future King of Asgard.