Here are some summaries of the characters in the book, sorted by order of relevance in the book. This should help if you have questions about the characters or just curious, so enjoy.
Jason
The narrator of the story and Carter's best friend, Jason is just an ordinary teen. After convincing Carter to take on the case, Jason himself is unwillingly brought along as Carter's partner. He does not have many hobbies, however he does occasionally work for the school paper (without Carter's knowledge) where he met May, a girl he obviously has a crush on.
Carter
Jason's extraordinary friend, Carter, while enjoying many things other teens like, is way different than other people his age. He has a few hobbies and interests that other teens would think a little strange. His biggest peculiarity is probably his opinion of school. To him, it's just part of an ordinary day, like others would view eating or sleeping. His amazing powers of observation led Jason to force Carter to take on the responsibility of finding who bullied Daniel Nathiel.
Principal Turman
The principal of Carter and Jason's school, Principal Turman appears to be a good and effective leader, one who is kind and caring yet will not tolerate disrespect and abuse. Despite the rumor that he originally wanted to be a business man, Turman takes his role of principal seriously. Even though he has his doubts, he allows Carter to try and find Daniel's attacker.
Daniel Nathiel
Daniel Nathiel is the victim of a terrible bullying incident. When he is found with a concussion, a broken arm, and a number of other bruises. He did not see his attacker so he willingly accepts Jason's suggestion of asking Carter to find the bully while he recuperates in the hospital.
May
A photographer for the school paper, May appears to be a kind-hearted girl who sympathises with those who are hurt. She appears to be fond of Jason though we do not know her exact thoughts (we can guess though). She is found to be a possible suspect for the mystery and this makes Jason try to find a way to prove she isn't.
Mr. Fris
Mr. Fris is the school janitor. When Daniel was bullied, it was Mr. Fris who found him and brought him to the nurse's office. A person in his mid-30's and the kind of guy anyone would love, Mr. Fris' job has made him memorize every inch of the school, which helps Carter as he tries to find the bully.
Karl Bruman
Suspect
Samuel Kayz
Suspect
Zoey Westers
Suspect
Harry Baclor
Suspect
Casey Millerz
Suspect
Susan Harps
Suspect
Hank Nuse
Suspect
Deliah Cassingway
Suspect
Gary Rectan
Suspect
McKinley Welders
Suspect
Raymond Dale
Suspect
Mrs. Wedd
French teacher
Mr. Wall
Physics teacher
Lucas Sarman
Suspect, never actually meet him