Multiverse, Universes, and what Infinity means

Disclaimer: I am not a physicist. What I say here is based on the assumption that certain theories are correct. I have in no way definitive proof (if such a thing could exist) that this is true. It's more of a thought process unraveling.

First, I'd like to point out that universe is essentially everything that exists. Because that, "multiverse" is really one big "universe" and there is only one "universe", hence the "uni".

If we assume that there is a number of universes so large that it is seemingly infinite, with different constants and/or different results of different actions, with more being created you read this, then it is only reasonable to expect that nearly anything is possible within these universes.

For example:

• A universe in which everything is the same as ours up until a certain point where something different happens, creating a "divergence" is extremely likely according to this model.
• A universe in which Earth was the same as it is today, except without the existence of humanity, is also equally plausible.
• A universe in which what we define as "magic" could, in theory, exist, provided there are physical principles that would allow such magic to exist. However, it is rather unlikely.
• Because of the oddness of quantum theory and wave functions, it is entirely possible that a universe exists in which "magic" happens not as a result of anything but simply because of random chance. This means that the entire story of "The Name of the Wind" or some other fantasy, magic-based novel could be real within that universe, not for any logical or physical reason, but simply because some highly unlikely things happened at highly unlikely times resulting in the seemingly impossible happening. With the large number of universes out there, it is possible.
• A universe in which everything was made out of LEGO bricks could, in theory exist, provided it had the physical principles which allowed ABS to come to live. It seems ridiculous, but it's a possibility. 

Those are just some of the many possibilities of certain theories being true. Unfortunately, it is unlikely we would ever be able to communicate with such universes, but were it possible, we would be able to observe things that were never thought to be possible. Or we might enter the universe and explode because we picked a universe in which instead of gravity there is only repulsive force. You never know.