Mark Grayson, better known as the superhero, “Invincible”, is the 17 year old half-human/Korean, half-Viltrumite son of Nolan Grayson (Omni-Man) and Debbie Grayson. Mark grows up as a normal teenager, idolizing superheroes and dreaming of becoming one himself. When his Viltrumite powers finally develop, he takes on the name Invincible and begins learning how to use his abilities while balancing superhero work with school, friendships, and family. Mark is compassionate, loyal, determined, and idealistic, believing that having incredible power means having a responsibility to protect people. However, he can also be impulsive, stubborn, emotional, and inexperienced, often struggling with the consequences of his choices. Mark is a tall, lean, muscular teenager with fair skin, short black hair styled is a loose slickback with a slightly tousled front, and brown eyes. His superhero suit is a fitting black bodysuit with a bright yellow central chest and abdomen panel extending into a high yellow collar and neck covering. The suit has blue shoulder sections, yellow elbow length fingerless gloves, and blue knee-high boots. The black sections cover most of his torso, arms, and legs, while the blue-and-yellow accents give the costume its distinctive superhero appearance. He also wears rounded, opaque white goggles that cover his eyes and a yellow mask that wraps around the sides of his face leaving the bottom half of his face visible. He possesses immense superhuman abilities, including incredible strength, flight, near-invulnerability, extreme speed, enhanced senses, rapid healing, and lifespans that can last for thousands of years, becoming stronger and more experienced with age.

Debbie is Mark’s mother and Nolan’s wife. She is a middle-aged Korean-American woman with a warm, approachable appearance, fair-to-medium skin, dark brown eyes, and black hair usually pulled back into a neat low bun. She typically dresses in practical, everyday clothing, such as a green button-up shirt, dark navy pants, simple flats, earrings, and bracelets. Debbie is caring, intelligent, strong-willed, compassionate, and fiercely protective of her family. She is a kind, caring, loving, patient, loyal, understanding person. She is supportive and loving toward Mark, encouraging him to become a good person rather than simply focusing on his powers. Despite being an ordinary human surrounded by superhumans, Debbie has remarkable emotional strength and refuses to let others intimidate her.

Nolan Grayson, better known as Omni-Man, is a tall, extremely muscular and broad-shouldered Viltrumite with fair skin, short black hair streaked with gray at the sides, sharp blue eyes, a thick black mustache, and a strong, square-jawed face. He wears his iconic white-and-red superhero costume, featuring a high red collar, white armored-looking torso, red gloves and pants, a red belt-like section, white boots, and a long red cape. Nolan possesses the incredible abilities of a Viltrumite, including immense superhuman strength, flight, extreme speed, tremendous durability, accelerated healing, enhanced senses, and the ability to survive and fight in the vacuum of space. As a warrior of the Viltrumite Empire, Nolan was sent to Earth under the identity of Nolan Grayson with the secret mission of preparing the planet for Viltrumite conquest. He married Debbie Grayson and had a son, Mark, eventually becoming a respected superhero known as Omni-Man. Although initially presenting himself as a loving husband, father, and Earth's greatest protector, Nolan's Viltrumite loyalty led him to brutally confront Mark after his powers developed, revealing the truth about his mission. However, his time on Earth and his genuine love for his family eventually caused him to question the Viltrumite Empire and its ideology. Nolan is stern, disciplined, proud, and intimidating, but beneath his warrior mentality he is deeply compassionate, protective, and capable of genuine love, especially toward his family. even though Nolan was a disciplined Viltrumite warrior, he still cares for his family and rather acts as a caring, understanding father toward Mark rather than a strict warrior.

Oliver Grayson, also known as Kid Omni-Man and later Young Omni-Man, is Mark Grayson’s 14-year-old half-brother and the son of Nolan Grayson (Omni-Man). He is half-Viltrumite and half-Thraxan, with light purplish-pink skin, short black hair, large gray eyes, and a lean build. His superhero suit consists of a red upper torso, dark-gray and black sections, a large chest emblem, red gloves, matching boots, and a red mask around his eyes. Born on Thraxa, Oliver initially grew rapidly due to his mixed heritage and developed a different understanding of morality because of his upbringing. Energetic, confident, curious, and eager to prove himself, he idolizes his father and brother while aspiring to become a hero. His abilities include superhuman strength, speed, durability, flight, enhanced senses, healing, and an extremely long lifespan. Although fiercely loyal to his family and genuinely eager to help others, Oliver can be reckless, aggressive, and willing to use extreme methods. As he grows older, he becomes more mature, learning empathy and developing his own identity while balancing his Viltrumite instincts with the compassion he learns on Earth.