In the midst of Oliver Queen's mayoral re-election campaign in 2013, an occultist known as Albert Davis was tricked by the Riddler into tapping the dark magic generated by his ancestors' secret shaping of Star City into an occult conduit. Albert (with help of other occultists, including Stanley Dover Elder) opened multiple gates across the whole city.
So, leading up to the events which have come to be known as "Hell on Earth" which happened within and around the city limits of Star City, Oregon, there was a rise in supernatural activity in Star City. I, personally, was in the city investigating that very subject matter and was witness to a number of these entities. I use the word "entity" deliberately as ghosts were not the only incorporeal being that plagued Star City during this time. Among a large number of ghosts of all manner drawn to the city, there were also demons of various orders, fae, daimons, and other supernatural oddities such as ectoplasmic constructs and various monsters. Why was the city such a hotbed of supernatural activity? That was due to the actions of the Order of Ancient Mysteries.
In 1987, a division of the Order of Ancient Mysteries managed to capture an Endless (a being of great psychic power), specifically the Lord of Dreams, Morpheus, or as some know him "the Sandman." The Order had not intended to capture that particular Endless, but they did make the most of this. With the Lord of Dreams captured, the Order of Ancient Mysteries used power siphoned from the Endless to enable them to explore and exploit the Dreaming in ways they had previously been unable. This became a particularly prevalent practice in Fawny Rig, England where the Endless was contained - until the members of the cult stationed there were killed off by a vampire infiltrator. But before that happened, the cult's harvested essence from the Endless made its way to the Order's other cells. This essence became a hot commodity among the Order after the rise of Norsefire made most remaining cells of the Order quite skittish about venturing to the English estate where their prisoner was held.
One of the more prominent cells of the Order of Ancient Mysteries existed in the heart of Star City, in the higher levels of Dillin Tower (formerly known as the Shandor Building). Ivo Shandor, a former grandmaster of the Order of Ancient Mysteries, had built the building to act as a conduit of esoteric power - channeling the city's psychic energy to a focal point on the building's upper levels. A modern member of the Star City cell of the OAM was Albert Davis. Mr. Davis was not a particularly adept sorcerer by any means, admittedly falling into the Order's ranks merely to pursue a "goth girl" he hoped to romance. After being rejected, Davis stuck around due to having made some friends within the Order (his first real meaningful social group) and also found that the Order had means to make his fairly miserable life more palatable. One such way was through lucid dreaming.
Davis had been given the assignment of conducting an inventory on the cell's relics. Most of the relics he found were beyond his skill level but there was one amulet of which he became quite fond. The foolproof amulet contained a special essence crystal that acted as an incubator, producing more of whatever essence it was fed. Davis had experienced a lucid dream during a group ritual which used up most of what little Dream essence the Star City cell had remaining, but in his cataloging, Davis found one more vial of the essence which he fed to the forgotten amulet. The process of replicating the potent essence of an Endless was slow, but the amulet produced enough 'juice' in a twenty-four hour period to allow one person, Davis, to practice a particularly vivid means of lucid dreaming on a nightly basis.
While Davis had only intended to use this as a private diversion, his nightly escapades in the Dreaming eventually would lead him to go exploring the castle at the center of the land. Davis had learned enough tricks in his prior lucid adventures to avoid the detection of the guards and servants of the castle. The only being that was likely to discover his trespass was sealed away in a basement in Wych Cross. During one of these explorations, Davis felt a tug at his consciousness that drew him to a cupboard where he found a jar filled with an inky black substance. The jar itself urged Davis to take it from the cupboard and shatter it on the floor, but when Davis touched the jar he set off a warding spell which summoned the castle's guardians and steward at once. In his panic, Davis left the jar and threw himself out the nearest window, causing him to awaken abruptly.
While he continued to explore the Dreaming, Davis did not return to the castle. He constantly found himself thinking about the jar and what it may have contained, but he dared not risk exposing his ill-gotten amulet to the castle's occupants. But while Davis was content to no longer seek out the jar, the same could not be said for the occupant of the jar's interest in Davis. The glass container was the prison of Azazel, one of the Fallen Lords of Hell, trapped there for his offending of Morpheus several years prior to the Endless' imprisonment in the basement of Fawny Rig. Azazel's limited connection to Davis gave the demon the means to track Davis through his limited ability to act in the mortal realm. When Azazel discovered Davis' access to the Order of Ancient Mysteries, Azazel began forming a plan.
Azazel confronted Davis, urged him into making a pact. Azazel's followers helped Davis with accumulating actual sorcerous power and relics which, in turn, allowed him to rise to the ranks of the Order's grandmaster within Star City (once the previous grandmaster was dispatched). In exchange for Azazel's help in helping Davis gain power, respect, and prestige, the newly-minted grandmaster used the Order of Ancient Mysteries to give the demon greater influence in the mortal realm... at least, that's all Davis thought he was doing. In truth, Azazel was also planting his own cultist and infernal followers within the ranks of the Order. With Davis easily bent by Azazel's manipulations, Azazel was able to use the OAM of Star City to lay the foundations for a grand plan. But in order to accomplish what Azazel had engineered, the OAM needed a greater source of power than the architectural conduit was harvesting. To that end, Azazel urged Davis to capture a being of immeasurable power, similar to the imprisoned entities of other cities and locations. Davis suggested the Endless in Wych Cross, but when the OAM ventured back to England to attempt a transport of their prisoner, they found Morpheus had been freed.
Around this same time, Azazel's activity had been discovered by the recently returned Morpheus. To remedy this, the Endless placed the glass jar in a cupboard with more powerful warding. While the demon could still exert some power on the mortal realm, it took him some time to develop countermeasures to his new confinement. During this period, Davis and Azazel lost contact with one another, and Davis was forced to devise an alternative means of finding a powerful entity. Whatever it was he found was not able to be properly confined or the esoteric properties of the Order's building were not aligned to those of the imprisoned entity. There was a lot of extra essence being bled out into the surrounding city, essence which drew supernatural predators and caused restless spirits to grow in power.
Enter Peter Venkman, Ray Stantz, and Egon Spengler. These three were parapsychologists at Seaview University. The three were involved in a long-term parapsychology study for the university. Ray spent most of his time in the field, interviewing people on paranormal encounters and collecting samples, Egon worked mostly in the lab, studying the samples collected by Ray and conducting experiments. Peter spent most of his time on the campus conducting interviews and experiments on the psychic potential of students, though this seems to mostly have been utilized as a means to score with beautiful young women as all of his male test subjects were regularly flushed out in the early stages of his interviews.
Ray had been monitoring the spectral activity at the Star City library when, one day, a very weak and minor spectre suddenly manifested into what Dr. Stantz documented as a "Free-Roaming, Vaporous, Full Torso Apparition" bearing the likeness of Eleanor Twitty, a former Head Librarian who had gone missing while documenting a large collection of materials supposedly on the occult which also turned up missing the same night as Twitty. Eager to investigate this using his partner's full range of abilities, Stantz quickly returned to the university to enlist the aid of Dr. Venkman and Dr. Spengler. The parapsychologists observed a number of other paranormal occurrences in the library before being scared off by the haunting spirit of Eleanor Twitty.
The three were fired from the university shortly after this incident, but they had yet to submit their findings and readings from the library to the university. Egon was confident that the data he had collected in the library, combined with Ray's technical ability, may allow them to devise a means to trap such entities for safer study. Of course, both Ray and Egon were stymied by how exactly to pay for the required gear and facilities. When Peter overheard this, he devised his own plan: opening a supernatural pest control operation - catching ghosts for profit.
What the three did not realize was that they had the right idea, at the right time, and were in the right place to receive a windfall of work.
Hell on Earth
In so doing, Davis accidentally unleashed a horde of demons upon Star City led by the notorious Trigon. The demons started attacking everything and everyone.
Ghostbusters quickly evacuated from ground zero and set up their base of operations at Ray's Occult Books. The bookstore was transformed into a command post, makeshift lab, and rudimentary barracks. Ecto-2 was transformed into mobile containment unit which served as the team's only containment unit for the duration of the crisis. with the demons and threats everywhere, more Ghostbusters were needed. The class of Ghostbusters 101 and Janine Melnitz were deputized and became Ghostbusters. There was one hitch, though. They didn't have enough proton packs. To help rectify that problem, Egon suggesting retrofitting Ron Alexander's proton packs. However, the Ghost Smashers were shut down and Ron wasn't willing to tell anyone where he stashed the proton packs before he went to prison. Mayor Queen pulled some strings and Ron was released from prison if he agreed to give over his proton packs and as part of his parole agreement, he was assigned to work off his debt to society as a Ghostbuster.
Stanley the Elder had summoned a demon many years prior, but had failed to bind the demon to his service because he didn't factor in that there was another named Stanley Dover, his grandson, in his bloodline when he prepared the ritual.
When the dark ritual happened, Old Stanley used the mass hysteria gripping the city to kidnap Young Stanley, even murdering the boy's parents in the process. Grandpa Dover took Stanley to an occult lair, warded from demons, where he planned to trade minds with the boy so that he could be the demon's master. But Spot managed to bypass the lair with the help of Stanley's uncle John Constantine. Enraged by the old man's evil nature, Stanley's Monster, Spot grabbed him and devoured him whole.
The filming of "War for Justice: Amazons Attack!" was interrupted by a demon gate opening in the middle of the set. Escaping hellspawn from the rift saw various actors and film crew including Marla Bloom, Danielle Cassidy, and Sharon Scott. Believing they were the actual heroes and not costumed performers, the hellions dragged the women back through the rift to curry favor with their hellish master, Nebiros. The demons also wounded Eddie Bloomberg.
Renet Tilley freed her master Savanti Romero who joined his infernal kin in the siege. While he was distracted, Renet returned to Savanti's palace and destroyed the totem that kept her bound to Romero's service. After enjoying a single day of true freedom, Renet turned herself into the Department of the Continuity, knowing there was a bounty on her for her crimes.
Hellboy and the BPRD were sent in to see what they could do about the situation. However, that turned out to be a bad idea, as it was akin to throwing gasoline on a bonfire. While thinking he was rescuing a pretty young blonde from a pack of demons, Hellboy broke away from his team to intervene only to discover the girl wasn't running from the demons but was leading them. As Hellboy realized his mistake, the girl's eyes turned black and then he was in for a much bigger surprise. She saw his right hand, smiled, and then greeted him as "Brother." While Hellboy was caught off-guard by this revelation, the demons rallied and swarmed the cambion, subduing him and taking him to meet his father. The other operatives of the BPRD tried to intervene, but were unable to effect a proper rescue due to the sheer volume of demons swarming the area.
When he met his father, by way of the proxy host his father's detached consciousness was possessing, Hellboy was told his true name and revealed his purpose as one of the Beasts of Revelation, sworn to aid the Lord of Chaos Trigon in purging the Earth of humanity. Azazel urged Hellboy to join him and take up his rightful place at his side, but Hellboy refused... initially. As further proof of his dark destiny, Hellboy was then subjected to the charms of the First of the Lilim, the Whore of Babylon herself: Ruby. Hellboy had studied enough of the lore to know that she was stated in the end-times to be riding a scarlet beast of blasphemy... and even just looking at her beauty made Hellboy uncomfortable. Before he knew it, her whispers clouded his mind. Her touch caused his filed down horns to grow tall and high. Her kiss caused a flaming crown to appear above his head. Just like that, Hellboy was gone and Anung Un Rama had been reborn. 
The whole demon invasion proved to be a trial by fire for the re-established Justice League and other heroes like Team Arrow, Titans and John Constantine. Task Force X was also dispatched, not to combat demons, but to capture Riddler. The group managed to get him, but an explosion caused by Emily Nashton (a member of Titans and Edward's daughter) let him slip away. Captain Boomerang knocked Enigma out and the Squad took her hostage. Velma Dinkley tried to close one of the gates, but it was too much for her. She was rescued by Norville "Shaggy" Rogers and his dog, Scooby-Doo.
After weeks of battling and waves of heroes coming to Star City's aid, the curse was lifted by the Green Arrow killing Albert Davis whose own lifeforce turned out to be the key needed to reseal the gateway he had opened.
Following this devastation, Oliver Queen's name was still on the ballot, but his heart was not in it. Shortly after winning the election, he announced he would resign and let his Deputy Mayor Frederick Tuckman take office. Oliver Queen then dedicated himself to using his company's fortune to bolstering Star City's development and restructuring. Jack Hardemeyer made Star City his new home, overseeing the removal of the city's residual infernal elements.
Oliver created "Paranormal Contracts Oversight Commission" to oversight Ghostbusters after giving them a large contract with the city.
Following the events of Star City's darkest days, Stanley and Spot went to live with Uncle John in Gotham. As John made for a poor guardian, Zatanna offered to take Stanley and his monster in at Shadowcrest where Stanley began to study magic with his many cousins.
This event would play a major part in the Justice League's decision to create a splinter team dedicated to handling occult threats such as this. The team was called Dark Justice.
Velma and Shaggy became friends, and when Daphne Blake offered Velma a job as a paranormal investigator, she convinced Daphne to also take Norville and his dog with them.
Danielle and Marla managed to come back from Hell. They offered blood to save Eddie. Unfortunately, the events changed Dani's blood and in the future Dani and Eddie turned into gluttony devils.
Dean Winchester is still dealing with his past experience during the demonic siege of Star City and feels that it changed him as a hunter. He both envies and pities his brother Sam for him not having been witness to the horrors there.
Renet Tilley was recruited by the DC and now as a way to make amends for her past transgressions she helps to stabilize the region's unstable dimensional integrity. 
Trivia and Notes
- The Teenage Mutant Ninja Turtles made their debut during this event. Because of their debut during a demonic siege, people think the Turtles are actually demons.
- Other groups that revealed themselves during this crisis include the Ghostbusters and the Metal Men.
- During these events Azazel possessed many people including Edward Nygma, Walter Steele, and Wally West.
- Immolation, Flagerethon and Gremlin tracked and tried to kill the Shame of Senael but failed.
- This event is based on the Green Arrow storyline "City Walls" from Green Arrow, Vol. 3 #35 - #39, Green Arrow: Quiver, Suicide Squad movie, and Ghostbusters movie, but with modifications.
Links and References
- Dinkley Files: Ghostbusting
- Network Files: Chad Fuller 2
- VOX Box: Hell on Earth 5
- Network Files: Samhain
- Roy Reimagines... Hellboy
- Earth-27 Journal: Star City
- Report Capsule: Zachariah
- NFX: Walter Peck
- Network Files: Stanley Dover
- Network Files: Emily Nashton 2
- Roy Reimagines... Supernatural
- Network Files: Zauriel 1
- Network Files: Renet Tilley
- VOX Box: Continue? 2...
- VOX Box: Turtle Power Prelude
- VOX Box: Hell on Earth 3
- Roy Reimagines... Suicide Squad