Deadpool is a fictional character that appears in comic books published by Marvel Comics. A disfigured and mentally unstable mercenary, Deadpool originally appeared as a villain in an issue of New Mutants, and later in issues of X-Force. The character has since starred in several ongoing series, and sharing titles with other characters such as Cable. The character is famous for his tendency to break the fourth wall and is frequently referred to by the moniker "Merc with a Mouth."
Deadpool's primary power is an accelerated healing factor, depicted by various artists and writers with varying levels of efficiency. Said healing factor, which was artificially endowed by the Weapon X program, enables him to regenerate any destroyed tissues or organs very quickly. However, his healing factor results in massive scar tissue causing his appearance to be deformed. The speed at which this healing factor works varies in direct proportion to the severity of the damage Deadpool suffers. Deadpool's healing factor is strong enough that he has previously survived decapitation more than once, though in each of these occurrences, his head had to be reattached to his body instead of his head growing a new body. Unlike Wolverine’s natural healing factor, Deadpool’s is mentally driven to a partial extent. As a by-product of his healing factor, he possesses enhanced strength, stamina, agility, and reflexes. At the time of the gene therapy that gave the character his healing factor he was dying of terminal cancer. An unanticipated side effect of the therapy was a rapid acceleration of the tumors as well, causing them to quickly spread across his entire body as soon as his powers fully activated. Deadpool's brain cells are similarly affected, which renders him resistant to telepathy.