Dragons, devils, etc, have set alignments,and thus by definition less free will than mortals. You can only play mortals in DnD. It's not haphazard at all.Just don't draw a haphazard line between what you can and can't play:
"You can play a warforged, but you can't play a shield guardian.
You can play a dragonborn, but you can't play a lizard man. Or a half-dragon.
You can play a tiefling, but you can't play a succubus, marilith, glabrezu, balor, dretch..."
Gnome: the Jar Jar Binks of the D&D Universe
Man, I am really sorry that you have such terrible players in your group. That has got to be a trial for you.
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There might be places above ground that would accept them, but even in my hobgoblin-run empire they wouldn't have much of a chance. Just because two species are evil doesn't mean they get along.
That's right. Let's get this out of the way. While I believe it is possible in theory to have non-human races that are fully fleshed out and aren't stereotypes and are roleplayed well, it never, or almost never, happens in fact. This is, of course, based purely on my anecdotal observations and personal experience, which is exactly the kind of irrefutable evidence that I prefer.