Madeleine Petsch as Davina Weasley.
Ben Barnes as Sirius Black.
Daniel Radcliffe as Harry Potter.
Emma Watson as Hermione Granger.
Rupert Grint as Ron Weasley.
Everyone should know any other cast members If you've seen the movies, Harry Ron and Hermione are a little older than this in later chapters but this is the age they start in the book.
And just to clarify this took me forever, every time I tried to publish it said there was a problem with an outside save, I don't know but it took ages that's why there's only 3 images for the cast members.