Invincible (Mark Sebastian Grayson) is a superhero created by writer Robert Kirkman and artist Cory Walker, currently drawn by Ryan Ottley.

Despite Nolan's pleas to join him, Mark refuses and begins dedicating himself to protect Earth from the Viltrumites, led by General Thragg, among other threats, while dealing with his own personal issues as he enters adulthood.

Eventually, Mark discovers that he and his father are the rightful heirs of the Viltrum Empire, as his grandfather, Lord Argall was the former ruler before being assassinated.

Over the course of their journey, Mark acquires the nickname "Vince" from Zephyr, befriending her alongside Duncan and Eddie, and forms a romantic relationship with Petra.

After failing to destroy the Reaver, who successfully conquers Earth in the future and consumes the Viltrumite Empire, killing Mark, Petra sacrifices her existence to destroy the Reaver and prevent his invasion from taking place, saving Mark in the past, who (alongside Duncan) retains a memory of her name and significance every time they awake.

The website claims: "This March the effects of IMAGE UNITED go global with a glimpse of the crossover's impact on INVINCIBLE and many other Image Comics favorites..."[citation needed] Due to his Viltrumite heritage, Mark Grayson possesses superhuman strength, speed, and durability, as well as the ability to fly, but is vulnerable to specific frequencies which affects his equilibrium and therefore his flight.

[7] After developing his powers at 17 years old, Mark discovers the harsh realities of being a superhero while struggling to define himself along with a berserker-esque rage that manifests as a result of his Viltrumite heritage.

[8] Mark Grayson / Invincible appears in a self-titled Gain Enterprises motion comic adaptation of his series, voiced by Patrick Cavanaugh.