I'm guessing somewhere in your memory there are a whole lot of traumatic events right? Normally I've never seen anyone but humans here but-- things were a lot different when I went to sleep yesterday. It's like everything changed overnight, people who I knew were here are gone, and now there are a bunch of newbies, a school festival, and all sorts of changes. But I'm pretty sure it should be the same basic rules or people who get into here: Something was wrong or unfair with what happened during your life and now you're stuck here, because you've got a will to live on, even after you died.

Also it's a school because pretty much all of the real people here were young enough to still be in or just out of school.