Ender's Game- Themes and Characters?

Hi, I read the book Ender's Game and I have to write an essay on it but i do not have access to the book. I've looked online but everything just seems to be a summary of the book. I was wondering if you could tell me the character traits of each of the characters (Ender, Valentine, Peter, Graff, etc.), and also the different themes in the book. Examples would help too. Thank you.