Some people do this all the time, but others aren’t aware that it’s totally admissible in D&D to change the theme or flavor of a class or race without changing the mechanics. Almost all DMs will allow this, and a lot of them encourage this. Even as a DM, you can create seemingly original NPCs that are really just reskinned core classes! Here are some examples that I came up with, but feel free to invent your own!
You can even do this during play. I once had a villain who went back in time and changed history. Each time it had this kind of effect on the PCs, not changing their mechanics at all, but changing the whole world and them with it. Mind you that was back in AD&D days…
