Maxperson
Morkus from Orkus
Sigh. Semantics and pedantry. It is impossible to add something without changing whatever it is that you added to. "Additive changes" is just sophistry trying to masquerade as something it's not. Adding "slave race" and "enslaves other races" CHANGES the races we're talking about. Salamanders used to have nobility too. That's gone. Why aren't you complaining about these changes. They've flat out CHANGED (and not even additive here, they've flat out removed something that's been part of that race since 1e) game lore. Why aren't you complaining? If canon was important, and subtractive changes are bad, why are you defending this?
The semantics are yours, though. An addition is not a change like is being discussed in this thread.
Nice dodge
It's not his fault you picked a bad setting for your example. Planescape is written so that two different lores, Prime and Planescape can exist simultaneously about the same topic.