Correct me if I'm wrong, but doesn't that seal up any alternate worlds in Riot's mythos besides the Void?
Anivia, Taric and sort of Nocturne (I think something about Fiddlesticks too?) used to come from alternate planes or worlds.
Anivia got retconned to Freljord, Nocturne just became a spooky Twisted Treeline dude and I can't even be bothered fact checking Fiddle but I'm pretty sure he used to have a few allusions to him being something from outside Runeterra.
Now Taric's a Demacian; no, not just a Demacian. An edgy Demacian.
Before this, he was the Ironman of Gem World; it was explained gems were the source of power from his homeworld and he was kitted up in them, shit was rad.
Now he's a Demacian tied to Targon OH BOY
(and I swear to fuck Riot if you make a point of making him gay SO HELP ME I WILL BE TRIGGERED; LEAGUE'S FIRST CANNONICALLY GAY CHARACTER PLAYING OFF OF STEREOTYPES AND A COMMUNITY JOKE CENTRED AROUND THEM)