What the hell. You can write any "prologue" you want. The only stipulation for an invite is because you have proven yourself in combat in some way that makes you stand apart from all the other two-bit sword swinging undead slaying dragon eating hero. You are unique if you cant build yourself a unique and interesting backstory "shrug". Wishes, sure what the hell if it helps your backstory have a wish as a prize to. A wish doesn't advance NoW lore only a characters lore and I am trying to build the NoW and its prize elements as part of the multiverse. So sure tack on a wish.