Tommy Jarvis

Thomas "Tommy" Jarvis is a character in the Friday the 13th franchise. He is one of the most recurring characters in the series, having appeared in three consecutive films. He is also widely considered to be the archenemy of the undead mass murderer Jason Voorhees, having faced and defeated him twice and survived both encounters, a feat that very few, if any, have repeated.

First encounter with Jason
Tommy was born in 1972 to Mr. and Mrs. Jarvis; by the time he was twelve, he developed a liking for making his own masks and make-up effects. Tommy was forced to fight for his life when Jason once again returned to Crystal Lake on his killing sprees, threatening both him and his older sister Trish. After an extensive chase, Tommy shaves his head and makes himself up to look like a young Jason, distracting him long enough for Trish to attempt to kill him with his own machete. Though she fails, Tommy takes up the machete and impales Jason through the eye, mortally wounding him. When Jason still showed some signs of life, Tommy lost control and desperately hacked away at his body to ensure his death, much to Trish's horror.

Pinehurst
Unfortunately, however, Tommy was left mentally scarred and spent the next four years of his life in and out of various mental institutions, suffering from constant nightmares and hallucinations of the killer. Showing signs of progress, Tommy was transferred to the Pinehurst Halfway House under the watch of Pam Roberts in the hopes that he would eventually reenter society. Unfortunately, after a brutal incident at the halfway house, local ambulance driver Roy Burns took on the guise of Jason and embarked on a killing spree as revenge for the death of his son; in the wake of this, Tommy began to lose his grip on reality. Ultimately, Tommy killed Roy in self-defense and exposed his true identity; nonetheless, this event seemed to push him over the edge, leading him to attack Pam while donning Roy's hockey mask ; fortunately, however, Pam managed to return Tommy to his senses and help him recover before things went too far.

Jason's Return
In 1990, when he was 18, Tommy escaped from the mental hospital and was intent on cremating Jason's body to finally rid himself of his demons; he traveled to Eternal Peace Cemetery with his friend Hawes and upon arrival, they both proceeded to dig Jason's corpse up; however at the sight of his old enemy, Tommy flew into a rage and impaled Jason's deceased body with a steel fence post before contemptuously throwing the killer's hockey mask into the coffin; unfortunately, the metal rod acted as a conductor for an incoming storm which was struck by lightening which brought Jason back alive and was more powerful than ever before; when he saw what had happened, Tommy fled the cemetery in horror, but not before Jason ripped Hawes' heart out and threw his body into his own exhumed coffin.

Fleeing to Crystal Lake, now renamed Forest Green to distance itself from negative publicity, Tommy attempted to warn the sheriff, Mike Garris, of Jason's return; unfortunately, Garris, aware of Tommy's troubled past, wrote him off as disturbed and put him in a cell for the night. When Jason began his killing spree anew, only Garris' own daughter, Megan, believed Tommy's claims. When Garris attempted to escort Tommy out of town, Tommy fled on route to the cemetery to try and show Garris Jason's open grave, only to discover that the groundskeeper, fearful of being implicated for digging up the grave due to his alcoholism, had covered the grave (and, consequently, Hawes's body) with dirt. Fed up, Garris handcuffed Tommy and took him to the city limits, warning him not to return.

Nonetheless, Tommy contacted Megan for help, having researched occult books and discovered a way to defeat Jason: he could be incapacitated by being trapped beneath the surface of the lake where he originally drowned as a child. Meanwhile, the pile of bodies that Jason had accumulated in the meantime only convinced the police that Tommy himself, acting out a delusion of Jason's return, was the killer. However, after pursuing Tommy and Megan to Camp Crystal Lake, Sheriff Garris and his deputies were attacked by Jason himself and killed. Nonetheless, Tommy managed to lure Jason out to the middle of the lake and chain him to a boulder; in the ensuing skirmish, Jason managed to drag Tommy under and apparently drown him. Megan swam out into the lake to save Tommy and was likewise attacked by Jason, but she managed to fully incapacitate him by ramming a boat propeller into his face before swimming back to shore and reviving Tommy with CPR.

Trivia

 * Tommy was originally meant to become the antagonist and "new Jason" in all post-The Final Chapter entries in the series, with the ending of A New Beginning leading into it; however, the poor fan reception prompted the producers to bring Jason back.