Although comic fans may have been waiting for years to see a 'faithful' adaptation of Vertigo Comics icon John Constantine (after the 2005 Keanu Reeves film) in Justice League Dark, TV has once again proven to be a more appealing medium. With NBC's Constantine bringing the supernatural side of the DC Comics/Vertigo universe to live-action, fans of the decades-long "Hellblazer" series star have their most faithful adaptation yet.

Some may already be dreaming of Constantine linking movie and TV, but the showrunners have wasted no time planting seeds for a larger universe of their own. The long term plan is unclear - especially given how much it's changed already - but the pilot episode alone contains more than a few easter eggs, comic book references and trivia for those who know what to look for.

Needless to say, there will be plenty of minor spoilers concerning the possible future of the show (for those who aren't already versed in "Hellblazer" lore) in our list of Constantine Easter Eggs You Might Have Missed, so read at your own risk.

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Ravenscar

Constantine Pilot Ravenscar Hospital

When audiences first meet John Constantine (Matt Ryan), it isn't in the middle of a supernatural ritual, or walking London's streets under cover of darkness, but as a resident of the 'Ravenscar Psychiatric Facility For the Mentally Deranged.' That's the exact location where the comic version of Constantine spent 3 years (1978-1980) following his first (failed) attempt at exorcism. In the comics, the facility would go on to become a hotel and was eventually owned by Constantine himself.

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Berchtold Equipment

Constantine Pilot Berchtold Vampire Easter Egg

In a truly odd bit of coincidence, the table upon which Constantine receives his electro-shock treatment is shown to be a Berchtold - a very real manufacturer of operating tables. But ask someone versed in horror about the rather unique name, and one piece of fictions comes to mind: "Ernestus Berchtold," a short story by 19th century writer John William Polidori.

Polidori's other famous work happens to be "The Vampyre"; the story largely credited for creating the modern idea of a romantic vampire. Both works came from the same summer holiday which spawned Mary Shelley's "Frankenstein."

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Dr. Roger Huntoon

Constantine Pilot Roger Huntoon Easter Egg

Though he's never mentioned by name, the doctor interviewing Constantine is shown to be one Dr. Roger Huntoon. Besides operating Ravenscar in the comic books, Huntoon is credited as the author of "Pow! Psychology: Understanding the Super-Men (and Women)" within the DC Comics universe. His distaste for superheroes has even led him to appear in comics like "Sandman," "Animal Man," and "Swamp Thing."

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Newcastle

Constantine Pilot Newcastle Comic

The cause of John Constantine's mental... troubles is ominously referred to as related to events that occurred in Newcastle; a very real city ('Newcastle upon Tyne') in northeast England. The show will offer a few insights into just what gory events took place in the town - and how it led to the eventual dissolving of 'the Newcastle Crew' - but for those who can't stand to wait, "Hellblazer" #11 (1988) reveals the story in full.

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Astra's Fate

Constantine Pilot Astra Comics

The pilot episode eventually offers a glimpse at what landed Constantine in Ravenscar in the first place. When his band, Mucous Membrane, stumble upon a gory murder scene at the Casanova Club, a possessed young girl by the name of Astra Logue is identified as the culprit. The exorcism obviously fails, and Constantine heads to Ravenscar for treatment willingly. But in the comics, he's deemed responsible for Astra's fate by the people treating (read: torturing) him.

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Nergal

Constantine Pilot Nergal Comic Trivia

The identity of the demon responsible for Astra's damnation is only given at the episode's conclusion: 'Nergal.' Demonic names may seem a dime-a-dozen to most, but John being unaware of Nergal's true name when summoning him to Newcastle was exactly why he lost control of the situation (explaining why finding 'Furcifer's name was so important). But Nergal is a key figure in Constantine's life for years to come; the pair will butt heads on multiple occasions, with John even receiving a transfusion of Nergal's own blood.

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Business Card

Constantine Pilot Business Card Easter Egg

This nod to fans appeared before the pilot even aired, when trailers showed John Constantine's business card to bear a 404 (Atlanta, GA) area code. Call the number yourselves and hear a voicemail message from Constantine directly, even dropping the name of Alec Holland - the man who would go on to become 'Swamp Thing' (which happens to be the Vertigo comic series where the exorcist was first introduced).

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Ritchie's Robots

Constantine Pilot Ritchie Simpson Robot Easter Egg

In the original series, Ritchie Simpson (another member of the Newcastle Crew) would eventually wind up being digitized inside a computer, with the intention of being 'downloaded' into a new mechanical body - before being fully transformed into a techno-demon. The version of Simpson (Jeremy Davies) viewers are introduced to is quite different, but his future is teased in the wealth of toy robots (including a prominent 'Mr. Machine') decorating his office.

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Ivy University

The Atom Ray Palmer DC Comics

With Ritchie Simpson given a significant academic promotion - now a PhD in Metaphysics - it's the school at which he teaches that's of note to DC Comics superhero enthusiasts. Ivy University may sound like a generic name for a place of higher learning, but it's the same school where Ray Palmer (and later, Ryan Choi) is also employed.

Palmer might be better known by his Justice League alter ego: 'The Atom.'

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Helmet of Fate

Constantine Pilot Fate Helmet Nabu Easter Egg

The artifact picked up and examined by Liv (Lucy Griffiths) won't just be familiar to DC Comics faithful, but Smallville fans as well. The golden helm is best known as the Helmet of Fate, able to grant its wearer incredible magic superpowers. The title - and helm - of 'Doctor Fate' has passed to a few people over the years, but the helmet itself remains one of the single most powerful magic objects in the entire DC universe.

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The Ibistick

Constantine Pilot Ibis Ibistick Comic Easter Egg

Comic fans may be so distracted by the Helmet of Fate that they miss yet another comic icon tucked in behind it: the Ibistick. Originally a creation of Fawcett Comics, the Ibistick was a magical wand forged in ancient Egypt for Prince Amentep. Amentep used the wand - capable of doing almost anything the bearer could imagine - to preserve both he and his dying love. Waking in modern times, Amentep took the name of Ibis the Invincible. Could such a story be planned in the world of Constantine?

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Pandora's Box

Constantine Pilot Pandoras Box Comic Easter Egg

The 'three-eyed' skull seen among the other magical artifacts may seems just as mysterious, but it's actually a far more recent addition to the DC Comics universe. The 'skull' is really Pandora's Box, the source (like the ancient Greek myth) of all the world's sin, allowed to escape thanks to the irresponsible actions of Pandora. The object played a large part in DC's New 52 "Trinity War," but given the heroes pulled into that conflict (including John Constantine and Shazam) we doubt it's more than a subtle nod to readers.

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Backwards Writing

Constantine Pilot Zatanna Writing Easter Egg

Not every easter egg found in Jasper Winters' collection takes the form of an object, as a scrawled message on one chalkboard reads 'More Than This' - backwards. There are plenty of reasons for eccentric minds to write reversed, but in DC Comics' realm of magic, the power held in reversed commands is generally saved for Zatanna, one of DC's greatest magic-users.

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The Medusa Mask

Constantine Pilot Medusa Mask Psycho Pirate Easter Egg

There is yet another piece of headgear worthy of note in Jasper's collection: the Medusa Mask. Initially beginning their lives as three masks, the faceplates created by Charles Halstead to control a range of emotions were forged into one by Roger Hayden - better known as 'Psycho-Pirate.' The combination resulted in a single gold mask (capable of controlling the emotions, memories, and minds of his victims) completely featureless aside from a pair of eyeholes, visible on Jasper Winters' mantle beside his time-distorting mirror.

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First of the Fallen

Constantine Pilot Easter Egg First of the Fallen

A reference to "The First of the Fallen" may seem as fitting a name as any for a 'Devil-like' figure residing in Hell, but for Vertigo readers, that name is anything but a common title. The number of 'fallen' divine beings has grown over the years thanks to Neil Gaiman's "Sandman" mythology, but The First of the Fallen (or simply 'The First') has remained one of the key antagonists to John Constantine in particular.

Although plenty of rulers have been banished to Hell after The First - followed immediately by The Second, and The Third, though not to be confused with Lucifer - he remains one character with a personal grudge against the show's lead.

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No Smoke, But a Light

Constantine Pilot Lighter Easter Egg

Much time was spent in Constantine's early days discussing whether or not NBC's incarnation of the title character would be a smoker. It may seem trivial, but both Constantine's pack-a-day habit and the cancer it brought with it are considered key elements of the exorcist by many. The pilot shows that John has, indeed, kicked the habit - but the non-tobacco portion of his addiction remains.

In the comics Constantine's lighter is typically concealed, but TV viewers get several chances to see it in full view; particularly during the final climactic battle. And as a means of getting around the producer's restriction of actually showing John smoking, expect the final bar scene's opening - showing him putting out his cigarette - to be a sign of things to come.

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Chas Chandler's Cab

Constantine Pilot Chas Chandler Taxi Easter Egg

Chalk this one up as another possible freak coincidence: joining John Constantine in his adventures, as always, is Francis William 'Chas' Chandler. While the TV series is taking some liberties with Chas'... mortality, it's the actor in the role we're interested in. Charles Halford will be best known to many viewers for his role in HBO's True Detective, suspected at one time to be the mysterious crime kingpin dubbed 'the Yellow King' being sought by the show's protagonists.

Credit either chance or some clever production designers, but Chas' trademark taxi has some notable markings - particularly the logo of 'Yellow Crown Cab Co.'.

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Conclusion

Constantine fire hands

Those are all the Easter eggs, bits of comic book trivia, and subtle references fans can look out for, but if you have any that we missed, please share them in the comments.

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Constantine airs Fridays @10/9c on NBC.

Follow Andrew on Twitter @andrew_dyce.