The character of John Constantine was created by comic-book writer Alan Moore. He first appeared in Swamp Thing Vol. 2#37 (Jun. 1985), and then featured in his own comic called Hellraiser. His access to powerful mystical forces and his knowledge of arcane rituals allows him to cast magical spells and battle demons. He appears always with a trench coat and cigarettes. He toured with a punk-rock band and spent time in a mental institution. He comes from Liverpool, England, where he tragically lost his family as a child, travelled throughout Europe until moving to New York City.

He is not always the hero and can be negligent of social mores. He battled the Cult of the Cold Flame and June Moone and the Enchantress, who also fought the Suicide Squad. He was a member of the Justice League Dark, along with Madame Xanadu, the vampire Andrew Bennett, and Cane, the Sire of all Vampires. He is a cynic and communicates with both angelic and demonic forces. He is dying of lung cancer and wishes for salvation from Hell because of a suicide attempt in his youth. It is to earn favor in Heaven that he sends demons to Hell.

The film begins in the Mexican countryside, where a scavenger named Manuel (Jesse Ramirez) finds a spearhead wrapped in a Nazi flag in the ruins of an old church. It is the head of the spear that killed Christ. In Los Angeles, Father Hennessy (Pruitt Taylor Vince) calls in Constantine (Keanu Reeves) to exorcise a demon from a young girl. Contrary to an agreement between God and Lucifer, the demon is trying to break through into Earth. Afterwards, Constantine meets with the androgenous half-angel Gabriel (Tilda Swinton) who refuses to let him off the hook regarding his damnation.

After being assaulted by another demon, he visits Papa Midnite (Djimon Hounsou), a witch-doctor club-owner who does not believe demons are crossing over. Then he comes into conflict with the half-demon Balthazar (Gavin Rossdale). A woman named Isabel Dodson (Rachel Weisz) commits suicide in a mental hospital. Her twin sister, Detective Angela Dodson (also Rachel Weisz) asks Constantine for help because her sister spoke his name. After they are attacked by winged demons, he agrees to help.

With the use of a feline familiar, he goes to Hell and sees Isabel damned eternally. He brings back her hospital wristband. As he explains to Angela, he himself committed suicide as a teenager to escape his persistent demonic visions, went to Hell, and was brought back by paramedics. Father Hennessy finds a mark on Isabel’s wrist. The demon Balthazar drowns him in alcohol to stop him from informing Constantine, but Hennessy reproduces the mark on his own palm with a corkscrew before dying.

In the hospital room, Constantine and Angela find a clue pointing to a prophecy in the Satanic Bible, which tells them the mark belongs to Lucifer’s son Mammon, who will try to claim Earth as his kingdom. Angela says Isabel, a clairvoyant and psychic, was committed to the mental hospital by their parents. Constantine awakens Angela’s own powers and learns that Balthazar is involved. Balthazar reveals that Mammon has the spear stained with Christ’s blood. Angela is possessed.

Constantine convinces Papa Midnite that the demons are breaking the rules. He obtains Angela’s location. With his helper Chris (Shia LaBeouf) he fights his way through a demonic army to exorcize Angela. Constantine witnesses an invisible entity killing Chris, which turns out to be Gabriel, angry because God prefers humans. Gabriel wants to unleash Hell on Earth. Constantine slits his wrists, knowing that his is the only soul that Lucifer would come to collect personally, and when Lucifer (Peter Stormare) arrives to take his soul, he tells Lucifer Gabriel’s plan. The two angels confront each other.

Lucifer burns Gabriel’s wings, making him mortal, and sends Mammon back to Hell. Constantine gets a wish, and he asks for Isabel’s release to Heaven. Lucifer realizes that Constantine’s act of selflessness means he cannot send Constantine to Hell. As Constantine begins to rise toward Heaven, Lucifer restores his life by curing his cancer, hoping he will damn himself some day. Chris in a post-credits scene ascends to Heaven.

The film was directed by Francis Lawrence, written by Kevin Brodbin and Frank Cappello from the comic. In the beginning, Nicholas Cage was to star. In the comics, Constantine resembled Sting and had an English accent, but this was changed for the American audience. To make Constantine seem more lonely, his half-breed demon lover Ellie (Michelle Monaghan) was excised from the film. Keanu Reeves and Tilda Swinton were praised by critics, but the movie generally did not get good reviews. The director wished the studio had let him make the film as dark and scary as he wanted to.

The Spear of Destiny prop was the same as in Hellboy. The film was called Constantine instead of Hellraiser because Hellboy was coming out at the same time and audiences might be confused. The holy hand-grenades were Christmas ornaments filled with water—not the same as in Monty Python. The cigarette lighter with Saint Benedict on it was created by Zippo for the movie. Speaking of the damned, Mel Gibson and Kevin Spacey were considered for the lead role. The creatures were created by Stan Winston Studio, with Ve Neill. The movie has become something of a cult film lately, with a noir anti-hero, Hell as a vision of Los Angeles after a nuclear attack, and a host of cool demons and angels.