He falls in with a group of young pickpockets trained by an elderly mentor named Fagin, the villainous Bill Sikes, and the Artful Dodger. After facing danger and capture, Oliver ultimately finds a loving home and a family of his own. Kaz and Oliver have been best friends since preschool, each of them has the other's back and their friendship always comes first. While Kaz is the “accelerator,” Oliver is the “brake.” He's a bit superstitious and cautious, but will take risks when it is needed.

Kaz and Oliver have been best friends since preschool, each of them has the other's back. Most likely to be voted as “class clown.” Kaz may be reckless and impulsive, but end of the day he’ll always put friendship first. Kaz is a laid-back guy who, unlike Oliver, doesn't think before his actions. He is outgoing, fun to be around and brave. When Kaz first started working at Mighty Med, Horace wasn't as sure on hiring Kaz as he was for Oliver. However, with some mistakes along the way. he can be just as trustworthy and a great employee. His favorite superhero is Tecton and when he is brought to the hospital Kaz tries to fix him but accidentally leaves a hole in his stomach. He knew that it was all his fault that Tecton wasn't healing, Kaz can eventually admit to being wrong.

Skylar comes from the volcanic alien planet Caldera. She originally starts as one of the universe's greatest superheroes before her archenemy, The Annihilator, steals her powers and turns her into a villain. After her powers are drained for her own safety by Hapax the Elder, she spends time as a powerless "normo" relying on her tactical skills and agility. She uses the human alias Connie Valentine while on Earth. As a Calderan, she possesses superhuman strength, agility, durability, and flight.She briefly regains her powers later in the series, though she has to work to control and remaster them due to occasional glitching. Skylar Storm is a comic book superhero who doesn't give up easily. She lost her powers because her arch-nemesis, The Annihilator, took them away from her. Even though she has lost her powers, she doesn't like to believe so. Once she tried to lift up a weight thinking that her powers would be restored but they weren't. She tried to burn a piece of bread, but that didn't work either, and she angrily threw it at the wall. Skylar sometimes helps Kaz and Oliver with their errands because she is bored without her powers. Skylar soon joined Logan High School since she realized that she isn't getting her powers back anytime soon. She wishes one day, she can regain her lost glory.

Alan is the son of the superhero Optimo and the nephew of Dr. Horace Diaz, the Chief of Staff at the secret hospital. He is sent to work and train at the hidden hospital to learn the superhero medical profession. Alan dislikes ordinary, powerless humans whom he calls "normos". He tries hard to get the human characters, Kaz and Oliver, fired from the hospital. Alan can move objects using only his mind, He also learns how to morph his body into different animals

Horace diaz is actually Caduceo, an immortal superhero and legendary healer. He is over 3,000 years old, having been born around 991 B.C. He has the power to restore a dead person to life five times. He serves as a father figure to main characters Kaz, Oliver, and Skylar Storm. He is the hospital’s Chief of Staff, and is later revealed to be Caduceo, the legendary healer of superheroes. Horace was born almost 3006 years ago in the year 991 B.C., and eventually became known as the legendary healer of superheroes, Caduceo. Gifted with the power to restore a dead person to life five times, he used three of them at various points during his life and the fourth to save Skylar Storm's life. He also battled and defeated the supervillain Catastrophe, splitting him into Wallace and Clyde and retaining half of Catastrophe's Dyad of Nebulon. He went into hiding, and the hospital Mighty Med was established in honor of him

Gus is quirky, lacks normal social skills, and often keeps strange items in his wallet or backpack. He is a friend of Kaz and Oliver at Logan High School, though he is initially unaware of their secret job at the superhero hospital. His family is very wealthy, and he later becomes the owner of the comic book store, The Domain. After the incident in Evil Gus, his abilities have been removed due to Kaz and Oliver curing him. All of the powers he obtain were returned to the original owner and on this page are former