You want to hear a fact? Okay

The Dementors were based on Rowling’s struggle with depression

The Marauders created the Map to insult Snape only. (And to not get caught making trouble!)

All death eaters are in slytherin

No some are not @Realhhhk

Example: Peter Pettigrew.

Yep

And Cedric Diggory in a alt universe(in the cursed child)

Peter Peteigrew (I don’t know if I spelled his last name right) Was actually in Gryfindor, even though he ended up a death eater.

Lily was pregnant when she was killed.

Really?

^I don't think its been confirmed. Some people said that JKR revealed it but we don't have proof.