Oh, here's a thought; What if this Twilit Wolf remained in Hyrule as a loyal Guardian to the Princess? Then, playing the Wolf, could either join the others, or remain beside the princess, simply over-viewing the quest, keeping her safe, and maybe, er, I suppose "Narrating" would be the right word... Actually, that does seem rather boring... I'm going to go with the story of "guarded the princess until the heroes leave on a quest"...