It seems like you can jump from universe to universe and the main universe is part of it as pulsfire Ezreal has an interaction for base Ezreal. My second question is if there is anyone from the canon universe that can jump from universe to universe? My guess would be Bard. Moreover, I find this idea of connected universes cool and would like Riot to further expand on that in the future.
there was a red post in 
s Q&A that said that she stole 
key from the Institute of War universe (pre-retcon). so it's somewhat confirmed that she can hop realities, just don't ask me to dig it up.
I kinda doubt that there'll be ever any kind of "universe-hopping" in the mainlore,though by now it looks like it is ok for the skinlore to do this.
I'm not really sure about how riot planned this out,but there is the connection between the dark stars and odyssey thanks to Rhaast and the way Rhaast talks about this sounds a bit like the dark stars aren't even from the same universe as the odyssey one,meaning that the dark stars might have the ability to travel to other skin universes,even if its extremely limited.
I believe it was implied the hoping exists in the other universes not the main one. And I would like it if it stayed that way
