Quite possibly. But not necessarily? I'm not anywhere near an expert but a new reality can be created by something as small as a decision that could be made different ways. And is, in the two different realities that spawn from those different decisions. Or they can be as disparate as planets and galaxies and entire sentient species being absent, or all but unrecognizable from one's point of view.
There are a great many more in depth explanations that probably have nuance I'm missing, but you'd have to ask Slav. He's the unchallenged expert in the field.
...and eccentric.
[A genius of the rarest sort. Thace is pretty sure he'd be a likable fellow in less stressful situations than their home reality, and is enough of a nerd to find the concepts Slav is an expert in fascinating. Unfortunately he's also well-grounded enough in their home reality to have a hard time understanding Slav who's... not. Probably.]
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There are a great many more in depth explanations that probably have nuance I'm missing, but you'd have to ask Slav. He's the unchallenged expert in the field.
...and eccentric.
[A genius of the rarest sort. Thace is pretty sure he'd be a likable fellow in less stressful situations than their home reality, and is enough of a nerd to find the concepts Slav is an expert in fascinating. Unfortunately he's also well-grounded enough in their home reality to have a hard time understanding Slav who's... not. Probably.]