Why should the game just give you Luna? Earn it like everyone else. And if you're having such an issue with Sleeper, go get it and use it like everyone else. All you have to do is a quest, a rather easy one at that. It's not like it's a random drop. And if you have an issue about being forced to use a certain weapon, welcome to something with a meta. No one is going to force you to use Sleeper, but if you want to win, that's your best bet. I'm not saying you can't win without Sleeper, but you'll have better odds with it.