Realities that follow fictional worlds question!

Regarding fictional or game or show or anime DRs or anything you want to call it how does that work. Like do those realities really exist and how if they have magic and things of that sort or otherwise supernatural things like powers or abilities? It’s just a genuine a curious question regarding if fictional worlds we see in media are plausible realities or if they have their limitation and rather if it is possible how? I’m kind of new to this and just wanted to grasp info and understand.