Susannah Simon - Likes to be called Suze. Sixteen years old. She is a mediator and aids in the passing on of ghosts. She moved from New York to Carmel, California when her mom got married to Andrew (Andy) Ackerman. She now gained three stepbrothers. Out of all the Ackerman boys, Suze is closest to David, who she nicknamed as 'Doc'. David was the only one who knew the most but very little about her ability. Suze quickly falls in love with Jesse, a 19th century ghost living in her bedroom though she tries very hard not to, and will do anything for him.
Father Dominic - The principal of the Junipero Serra Mission Academy. A fellow mediator. Calls Suze by her full first name. When asked, he replied that "Suze" sounded vulgar. He has dealt with many ghosts over the years. Just like Suze he fell in love with one before he became a priest, but he still doesn't approve of Suze and Jesse's relationship. It's obvious he cares for Suze deeply. He and Jesse seem to get on well as they are both old fashioned in their morals and views on certain subjects.
CeeCee Webb - One of Suze's best friends in Carmel. She is an albino and once described herself as "Tweeny Bird" of her (and Suze's) grade. Has a huge crush on their friend Adam. She is the school newspaper editor. Ceecee knows everything about everyone in school and lots of facts about the people in their town. Knows a little about Suze's secret, and Jesse.
Helen Simon-Ackerman - Suze's mom. Calls Suze "Susie". Works as a news reporter. She relocated to California, since she had one child and flexible job. On the other hand Andy has three kids and his own business. (although Suze's mother has no official name. When asked Meg said she named all mothers in books she was writing at the time Helen.)
Andy Ackerman - Suze's stepfather. He can cook practically anything. He fancies himself a bit of a comedian, despite being not that funny. He's very nice to his children and almost immediately treats Suze as his own.
Adam McTavish - One of Suze's best friends in Carmel. Is oblivious to CeeCee's crush on him. Is attracted to Suze when he first meets her.
Jake Ackerman - Referred to as "Sleepy" by Suze in the first couple books. The eldest of Andy Ackerman's sons. He is a year above Suze and Dopey in school. Jake works as a deliverer at Peninsula Pizza and is saving up for a camaro. He very rarely speaks unless spoken to directly, or if it's a subject that deeply interests him. Sleepy loves to surf, and is known as a "hottie" throughout Suze's school.
Brad Ackerman - Referred to as "Dopey" by Suze in the first couple books. The middle of Andy Ackerman's sons. He mainly talks about wrestling, girls, parties and protein shakes. He's your average popular high school jock. Suze liked him least out of all her stepbrothers.
David Ackerman - Referred to as "Doc" by Suze in the first couple books. The youngest of Andy Ackerman's sons. For the most part, he knows about Suze's secret. He has red curly hair and sticky out ears. David is very intelligent and has been offered a chance to skip a grade, but refused. Was contacted by Jesse who was trying to save Suze's life. He blamed himself for his mother's death.
Jack Slater - A young boy Suze is required to babysit for her job. He is very shy and hates going outside. A fellow mediator that Suze takes under her wing. He becomes a different boy when he meets Suze. She reassures him about the ghost problem and boosts his confidence in himself.
Paul Slater - Jack's older brother. Calls himself a shifter. He stresses that he is not a mediator. Has less than good intentions for most of his role in the books. He appears for the first time in the fourth novel, were he develops an obvious passion for Suze. He doesn't like the fact that he can't win her and transfers to her school to get closer to her. He doesn't really like Jesse who shares the feeling. He knows many things about mediators that Suze can't help being interested in.
Kelly Prescott - One of the most popular and richest girls at school. Student body president. Has a very obvious crush on Jake, but tries to hide it. Also develops a later crush for Paul Slater. Dopey's main crush.
Debbie Mancuso - One of the most popular and richest girls at school. Has a very large crush on Brad and he seems to return these feelings. Tries to copy Kelly but Kelly has always been more popular.
Sister Ernestine - The assistant headmaster, or "vice-principal" if you will, of Junipero Serra Mission Academy.
Bryce Martinson- Jake's friend. He was nearly killed by his ex-girlfriend Heather, who is dead. Considered hottest guy in town by the girls.
Thaddeus "Tad" Beaumont, Jr.- Suze went out with him (briefly). Obsessed with basketball, also one of Kelly Prescott's crushes. Suze gave him a poison oak rash on his neck when she danced with him at Kelly Prescott's pool party.
Thaddeus "Red" Beaumont, Sr.- Thought he was a vampire for awhile. Suze believed he was the killer before she found out about Marcus.
Marcus Beaumont- Tad Beaumont's Uncle. Killer.
Aunt Pru - CeeCee Webb's aunt who believes she's psychic. She claims that CeeCee was Cleopatra in her past life. Suze says "she is a card missing from a full deck"
Michael Meducci- A psychotic murderer who dates Suze briefly.
Gina Augustin - Suze's best friend from Brooklyn. Both Jake and Brad tried to gain her attention during her stay at California in the third book.
Rick Slater - Jack and Paul's dad.
Nancy Slater - Jack and Paul's mom.
Caitlin - Suze's boss at the Pebble Beach hotel. Jake goes out with her.
Dr Clive Clemmings, PhD- The boss of the local History Society who has a heart attack when he sees the ghost of Maria De Silva. Or you could say Maria kills him, along with his grandfather.
Neil Jankow- Brother of Craig Jankow who was killed by a boat sinking.
Dr. Slaski - Paul and Jack's grandfather. Insultingly called Grandpa Gork by Paul. His name was changed to Mr. Slater to hide his identity. He was the discoverer of shifting, and thought to be crazy in his prime when he published ideas of shifting and time travel.
Mrs. O'Neil- Suze's house used to be a boarding home. Mrs. O'Niel was the owner of the boarding home.
Shannon- David's crush.
Madame Zara - A Tarot-Card-Reader only mentioned in the books. She sensed Suze was a mediator, and said it in front of Gina Augustin. She read Suze's cards and depicted that Suze would only have one love but that it would last forever.
Spike - The orange tabby cat who is adopted by Jesse. Doesn't like Suze and growls when she is near. He was adopted by Suze after his owner died of cancer. He gets closer to Suze for a while when Jesse disappears in the fourth novel. Only has one ear.
Jesse de Silva - A 150 year old Spanish ghost living in Suze's bedroom. It's obvious he has feelings for Suze, as he is protective of her and saves her life on more than one occasion. Starts dating Suze in the sixth novel, after trying to stay away from her because he feels she should be with someone her friends and family can see. Comes back to life after Suze and Paul accidentally bring his body forward in time in the sixth novel.
Peter Simon - Suze's dad. He won't move on no matter how hard Suze pushes. Often, he pops up to check up on Suze and her mother. He also disapproves of the Jesse and Suze's relationship.
Cynthia - Appears in Ninth Key. She is later revealed as Andy's first wife-the Ackerman boys' biological mother.
Timothy - Previous owner of Spike, appears in Ninth Key.
Heather Chambers - Appears in Shadowland. Killed herself after her boyfriend broke up with her and haunted Mission Academy. Injured several people with her physic powers and caused a lot of property damage. Eventually exorcised by Suze when she could not be convinced to go on her way peacefully.
Felicia Bruce- Appears in Reunion. Killed by Michael Meducci when he drove the car she was travelling in off a cliff. She was a member of the notorious RLS Angels before she died.
Carrie Whitman- Appears in Reunion. killed by Michael Meducci when he drove the car she was travelling in off a cliff. She was a member of the notorious RLS Angels before she died.
Mark Pulsford- Appears in Reunion. He was killed by Michael Meducci when he drove the car he was travelling in off a cliff. He was a member of the notorious RLS Angels before he died.
Josh Saunders- Appears in Reunion. He was killed by Michael Meducci when he drove the car he was travelling in off a cliff. He was a member of the notorious RLS Angels before he died.
Maria de Silva Diego - Jesse's cousin, whom he was once engaged to marry. Had him killed so she could marry Felix Diego instead. Comes back in Darkest Hour to prevent Jesse's body from being found and keep her family's name clean. Tries to kill Suze on several occasions but is exorcised in the end.
Felix Diego - A gold digging slave trader who murdered Jesse in order to marry Maria. Comes back in Darkest Hour to prevent Jesse's body from being found. Throws Suze off a roof and eventually exorcised with his wife. Also appears in Twilight when Suze and Paul go back in time to prevent Jesse's murder. Is killed by Jesse this time around. Unaware of how his death affects the time stream.
Craig Jankow - Appears in Haunted. Died in an accident when he went sailing with his brother, Neil. Believes that Neil should have died instead of himself and attempts to drown him.
Mrs. Gutierrez - Appears in Twilight. Wants Suze to give her family some money she buried in the backyard.