Wht is the story about the summoner rift and summonet itself ?

I heard a long time ago that riot wanted to revisit the whole story about league since before champion entering the league actually had reason and a backstory behind but now i just feel like why would you enter the summoner rift if youre a person like kai'sa who just got out of the void or rek'sai whos a hunter void seeker ( i mean how did she even find the place by any mean first ) .