A main symbol in this book is a peregrine. It is one of the main symbols because Miss Peregrine can transform into said bird.
This is the main protagonist: Jacob. Jacob is just an "average" rich kid (average characters usually have specially powers or they actually are average and rich kids are usually stuck snobs or hate their wealth) Jacob loved his grandfather, so when his grandfather wanders out of his house and then get's killed, he looks for clues, which will then lead him to an island where the story gets interesting.
This is our main antagonist. Dr. Golan. Even though he isn't an antagonist at first, he becomes one closer to the end of the book. *spoiler alert* He dies due to the fact that even wights (read book to find out more vocabulary) are mortal, especially if they get shot in the head and then fall of a light house.