Mac is a resourceful sixth grader who runs a lucrative, secret business in his elementary school. Operating out of an unused bathroom stall, he arranges favors, provides loans, and solves problems for his peers for a fee. He saves his profits with a singular goal of buying Chicago Cubs World Series tickets. His confidence allows him to tackle large problems, though his physical size leaves him vulnerable to older aggressors.

Vince is Mac's best friend and the financial brains behind their underground school business. He keeps meticulous records of their funds, expenses, and customer debts. As a talented pitcher and avid Chicago Cubs fan, he shares Mac's dream of attending the World Series. He often offers cautious advice and serves as the voice of reason when business risks escalate.

Staples is a legendary local criminal who runs an extensive illegal sports betting operation that infiltrates the elementary school. He uses threats, extortion, and physical violence to ensure his bookies and gamblers pay their debts. He commands a loyal crew of older high school henchmen to enforce his rules. His expansion into the school directly threatens Mac's business.

Fred is a frightened third grader who finds himself in over his head after working as a bookie. He places bets for students but wants to quit the operation out of fear. His request for protection brings a new level of danger to Mac's business. He spends most of his time quietly playing video games on his DS while hiding in Mac's office.

Tyrell is a secretive student who operates in the shadows of the school. He works as an independent spy-for-hire, utilizing disguises and stealth to gather information without detection. He prefers solitude and charges a premium for his highly effective surveillance services.

Kitten is a sixth-grade student who serves as Mac's top bully for hire. Despite his neat clothes, small stature, and sweet appearance that easily fools adults, he possesses a ruthless trickster personality. He operates seemingly without a conscience, making him highly effective at intimidation.

Joe is a large, dependable eighth grader employed by Mac. He acts as the official bodyguard and bouncer for the fourth stall office. He keeps clients in line, manages the waiting area, and provides physical backup when Mac faces threats from older students.

PJ is a high school student who acts as the primary enforcer for the local gambling ring. He drives a recognizable car and uses his size and age to intimidate younger elementary school students. He follows orders to track down debtors and those who interfere with the betting operation.

Known primarily as the Collector, Barnaby is an eighth grader who works as a heavy for the local betting ring. He physically attacks students who fall behind on their gambling debts. He targets anyone who attempts to help debtors escape their obligations.

Justin is a seventh grader who manages the day-to-day illegal betting operations inside the elementary school. He coordinates the lower-level bookies and ensures money flows upward to the ring's leader. He relies on older henchmen for protection when threatened.

Robert is an elementary school football player and one of Mac's clients. He promises to take a girl to a restricted movie but lacks the means to gain entry. He agrees to owe Mac a future favor in exchange for the necessary connections.

Jacky Boy is an elementary school student working as a bookie. He takes bets from younger students and pressures them into 'double or nothing' situations to increase their debts. He cracks under pressure when confronted by Mac and his hired bullies.

Ears is a student who previously worked as a reliable, cheap informant for Mac's business. He recently accrued gambling debts and was forced into an arrangement that prevents him from sharing useful intelligence. He fears for the safety of his cat if he breaks his new rules.

Mac's father is a supportive parent who expects his son to take responsibility for household chores and messes. He historically steps in to protect Mac from older bullies, though he remains unaware of the true scale of his son's school business.

Mac's mother is a caring and generous parent who looks after her son's daily needs. She is welcoming to visitors, unwittingly offering snacks to dangerous individuals who show up at their home pretending to be Mac's classmates.

Vince's mother is a hardworking parent who recently lost her job, causing significant financial strain on her household. Her struggle to find new employment forces her family to make difficult sacrifices to pay for food and necessities.

Brady is a third grader whom Mac employs for low-level security tasks. He attempts to earn extra cash by guarding clients, but he secretly carries massive gambling debts that compromise his reliability.

Nubby is a mean, overweight seventh-grade bully. He has physical nubs for fingers on one hand. He operates as muscle-for-hire when Mac needs to intimidate members of the gambling ring.

Little Paul is a surprisingly tough second grader who never backs down from a fight. Despite his young age, he serves as an effective distraction and combatant in Mac's mercenary squad.

Snapper is a third-grade girl whom Mac hires for her aggressive tendencies. She bites others hard enough to draw blood and refuses to let go. Her unusual fighting style makes her an effective component of Mac's intimidation team.

The Hutt is an eighth-grade bruiser whose nickname derives from his resemblance to a famous movie alien. He provides significant physical weight to Mac's hired crew during schoolyard confrontations.

Kevin is a seventh grader known around the school for stealing lunch money. He brings his experience in schoolyard intimidation to Mac's organized strike force.

iBully is a sixth grader whose computer hacking skills result in targeted cyberbullying. He avoids physical combat, instead using digital attacks to damage the reputation of Mac's enemies.

Great White is a thin, scrappy seventh grader from Britain. He fights hard and fast, making him a valuable asset when Mac needs to execute a coordinated attack against older students.

PrepSchool is a sixth-grade girl who specializes in spreading vicious rumors about others. Like iBully, she avoids physical violence and instead attacks the social standing of the gambling ring's enforcers.

Matt is an elementary school student who finds himself severely indebted to the local gambling ring. He owes an exceptionally high amount of money and fears physical collection, prompting Mac to take direct action against the ring's enforcers.