Hussar
Legend
But, as @Lanefan pointed out to you, rewriting areas based on the character level is verbotten in sandbox play. That's one of the most fundamental aspects of a sandbox as it's being described - that the world exists completely independently of the PC's. Altering areas just because the PC's happen to be level X and not Y is violating one of the most basic tenets of sandbox play.I mean, you just have the same opponents, but with different numbers of them or different levels of hit points and AC (lower or higher), stuff like that. Obviously that’s not going to help you if the PCs go to places with nothing but high-level opponents, like the Demonweb Pits or the Valley of the Ancient Dragons, but it will open up a lot more of the world to them without changing what’s actually there. If the PCs travel through Bandit Badlands, they still get attacked by bandits. They just meet, I dunno, eight bandits instead of fifteen bandits led by three bandit chiefs, or whatever it would be.
Which means that D&D, and any level based system, forces you to design worlds that take levels into account. It's unavoidable.