The Spectre is a DC Comics character. Basically, he's a superhero ghost, though in practice he has been everything from a supernatural serial killer (of criminals) to the Agent of God's Wrath over the years.
The character first appeared in "More Fun Comics" #52 (February, 1940), created by Jerry Siegel and Bernard Baily. In his origin story, the Spectre was Jim Corrigan, a police detective who was murdered by criminals. In the afterlife, he decried the injustice of his murder, and an unseen voice (later interpreted as being God's) granted his wish: he returned to life, but with supernatural powers that he soon used to kill his murderers.
At this point, other than in his physical appearance, Spectre was your typical supernatural avenger character. However at the time, superheroes were getting in vogue, so he was soon added to the roster of the Justice Society of America, and treated pretty much as any other superhero; he even acted and talked as casually as the others. He also found himself easily defeated despite his nonliving nature and his incredible powers, just so the other members of the group could have a chance to save the day. As for Corrigan, he just went on with his life, as if nothing had happened (his murder never having been discovered.)
The relationship between Corrigan and The Spectre varied over the years; at one point, they were actually separate characters, with The Spectre merely using Corrigan's body to "rest" when he needed to, much to the latter's chagrin.
The Spectre held his own series in "More Fun Comics" until issue #101 (January, February, 1945). He was regularly featured with the Justice Society in "All-Star Comics" #3-23 (Winter, 1940 - Winter, 1944). The character was then dropped for the following twenty years. He was revived in "Showcase" #60-61 (January-April, 1966). He also appeared in #64 (September-October, 1966), before gaining his own magazine. "Spectre" vol. 1 lasted for 10 issues, from December, 1967 to June, 1969. In the 1970s, the Spectre was revamped, now being taken back to his original horror roots: he would track down murderers and then execute them in some pretty twisted ways (for example, turning a hood to wood and then cutting him with a buzzsaw.)
The Spectre also found himself becoming more and more powerful: in his fight against Shatan (a poorly disguised Satan stand-in) they hit each other with planets. Spectre was eventually acknowledged as one of the mightiest beings in the DC Universe, even more so than the Silver Age Superman. About the only beings stronger were The Phantom Stranger and God himself. This limited him to making appearances only when the universe was threatened by supernatural menaces, and usually only long enough to fix some problem and then leave.
Post-Crisis, The Spectre was reinvented as the actual embodiment of God's Wrath. He had his own series again, which explored the reasons for his existence. Ultimately it was revealed that the Spectre was actually a fallen angel pardoned by God by being turned into his personal avenger and not just part of Corrigan's soul. Corrigan in fact was tired of living and willingly separated from The Spectre and went on to Heaven.
This left the Spectre without a host, which made it reckless; eventually he bonded with the then-dead Hal Jordan, who tried to twist the Spectre's mission from vengeance to redemption. This was later undone by Jordan's resurrection. Again left without a host, the Spectre was tricked by Eclipso (who ironically was once God's Avenger as well) into killing most of the magic-users in the DC Universe since she convinced him that "magic goes against God's will". (This turned out to be part of a larger Xanatos Roulette to recreate the DC Multiverse, as seen in Infinite Crisis.) He was stopped only by being bonded (by God) to Crispus Allen, another recently-murdered cop. (DC teased the audience by having his killer also be named Jim Corrigan.) He's still the current Spectre, who is trying to understand his role.
- Affirmative Action Legacy: The current host of the Spectre is an African American. Not quite "Black" since the Spectre is always whiter then the moon.
- All Crimes Are Equal: Has a tendency to believe this when not bound to a human host. Once when he was between hosts he went from murdering a serial killer (eaten by crows), then a cheating wife and her lover (strangled by their bedsheets), then a little boy who stole six dollars from his mother's purse (drowned in a sea of pennies), then a girl who spoke rudely to her father (beheaded), then a man who cheated on his taxes (impaled on a giant pen).
- The Atoner: The Angel Aztar, who was one of the rebellious angels, but apparently the only one that repented. As penance, he must fuse with the soul of a dead man and purge the world of evil. One sinner at a time.
- Baleful Polymorph: An usual punishment meted out by Spectre.
- Boring Invincible Hero: The Spectre is one of the most powerful beings in the entire universe. Needless to say, he hasn't hung out with a bunch of mere mortals like the JSA much since The Golden Age of Comic Books. A memorable run on his comics side-stepped this by having his pass judgement on morally ambiguous situations and focusing his choices.
- Bumbling Sidekick: Yes, even the Spectre had one in the Golden Age - "Percival Popp, the Super Cop."
- Cement Shoes: This is how Jim Corrigan became the Spectre in the first place.
- Crisis Crossover: Since Crisis on Infinite Earths the Spectre has fallen to the Worf Effect or been conveniently absent.
- Crossover Cosmology: In the DCU, every god is real.
- Cruel and Unusual Death: A specialty of the character
- Drama-Preserving Handicap: For a character as powerful as the Spectre he sure has a lot of problems.
- Deus Ex Machina: He's literally a walking Deus Ex Machina.
- Deus Exit Machina: A frequent victim.
- Flat Earth Atheist: The current host of the Spectre was an atheist- before God revived him as The Spectre.
- Fridge Horror: During The Interregnum and early Silver Age, the Spectre was forbidden to actually kill anyone. The writers got around this by having him do things like turn criminals into inanimate objects. Since the Comics Code Authority let him get away with it, they must not have realized exactly what they had done.
- Foil: Reporter Earl Crawford in the Jim Aparo series. While the Spectre believed in punishing criminals beyond their crimes, Crawford believed that wrong doers deserved a fair trial and a chance to face up to their crimes.
- Getting Crap Past the Radar: See Fridge Horror above. One point of the Comic Code Authority was that it said humans couldn't be set on fire. One comic got around this by removing the "Human" part of the equation and letting Spectre turn a criminal into a candle. There was no rule against burning a candle, even if it was screaming in pain as you did it.
- God Is Good: The Spectre is a superhero in that he avenges those who were innocent and cry out for justice. But...
- Good Is Not Nice: As cathartic as watching a child molester get eaten by his own doll collection is, it almost makes you wish that he was arrested and gone through the usual lax punishments inherent in the Human Justice System.
- See Throwaway Country below for a more extreme example.
- The Gods Must Be Lazy: The Presence only intervenes when it damn feels like it.
- Hero with an F In Good: He means well, but he got such a low grade in good that God keeps him bound to a human soul just to give him a cheat sheet.
- Joker Immunity: The Spectre once tried to pass Judgment on The Joker; he failed, because for all his viciousness, the Joker is still crazy, and thus not responsible for his acts.
- Karmic Death: The Spectre arranges these.
- Karma Houdini: The Spectre's purpose is arguably to make sure murderers don't become these. He doesn't punish every murderer; only those who would otherwise escape justice.
- Knight Templar: Has a tendency to go overboard. See (again) Throwaway Country, and also his plan to kill New York if an innocent man who had been found guilty was put to death, essentially because the case was titled that man "vs the State of New York". Sometimes his human host is portrayed as the only thing holding him back from being an Ax Crazy All Crimes Are Equal nutjob.
- Lovecraftian Superpower
- Monster Modesty: Despite being an all-powerful instrument of God, he has a strange knack for wearing as little as possible.
- Our Angels Are Different: The non-human half of the Spectre Entity.
- Our Ghosts Are Different
- Power Creep, Power Seep: Makes Superman's climb look almost puny.
Constantine: Sometimes it's one of the most powerful beings in the universe. Sometimes it's little more than a bloke in green tights.
- Powers That Be: The Voice, aka The Presence, aka God.
- Reality Warper
- Refusing Paradise - Done as a bit of a Sadistic Choice early on to The Spectre; the Voice (implied to be God) says he's now earned the ability to pass on to Heaven, one time only offer...just as his love interest has a bullet speeding at her head.
- Semi-Divine: The Spectre, as a dead human who is the host of (the angel that represents) God's Wrath/Vengeance.
- Throwaway Country: Vlatava, a minor European country, was completely slaughtered by the Spectre after passing judgment on it for war crimes, presumably even including the children. The sole survivors were two politicians, one from the opposed party of the other.
- Voice of the Legion: He speaks in fiery or dripping green speech balloons.
- Voluntary Shapeshifting
- What the Hell, Hero?: Happens very often, including burning an entire country to the ground.
- The Worf Effect: Has a tendency to get defeated by whatever villain writers are favoring that week.