Abaddon is a massive and ancient underground complex beneath the capital city of Rome. Its first chambers were build around the time Jesus Christ was crucified. Many more and deeper chambers were added up until the Late Middle Ages, making it the biggest underground complex in the entire world.
Many myths and legends surround Abaddon, one of which has been confirmed: namely, that the deepest chambers of the complex are prisons holding ancient and incredibly powerful entities which could potentially devastate the entire planet should they break free. It was also revealed that the Keeper, the guardian of Abaddon, is the sole reason why those entities are not capable of breaking free. As to who or what imprisoned the entities in the first place is unknown, though it is reasonable to assume that the Apostle's Wills and/or their hosts were responsible for that, considering the fact that the Keeper seems to share a very close relationship with them.
Purpose[]
The true purpose of Abaddon has always remained vague, though it has been confirmed that the Roman government uses Abaddon's upper chambers as a prison complex for dangerous supercriminals. Numerous sections of the Vatican Secret Archives are also stored down there. The upper chambers of Abaddon are maintained and guarded by the Guardians, human volunteers, who technically answer to the Roman government, but in reality answer only to the Keeper. Despite being very familiar with Abaddon, even the most veteran Guardians rarely if ever venture to its lower chambers.
Upper Chambers[]
Beast Quarters[]
The Beast Quarters is where Nikolas Oborski and his army of beastmen reside, as well as where the Will of Peter had been imprisoned. Having been denied acces to the City of the Damned by the Keeper and his Guardians, Oborski's beastmen attack and feast upon anyone ignorant or stupid enough to traverse their territory. The Quarters are connected to the City of the Damned.
City of the Damned[]
The City of the Damned is an ancient city within Abaddon which serves as a sanctuary for nonviolent prisoners, regardless of whether they are guilty of the crimes they have been sentenced for. It is also the place where the Keeper usually resides, as well as the meeting point between the Keeper and Roman delegates. The city and its inhabitants are protected by the Guardians. It can be reached through the Well of Souls.
Hall of Titans[]
The Hall of Titans is a gigantic circular chamber with a seemingly endless bottom. Across the wall are four truly enormous stone statues representing ancient warriors or soldiers. Within each of the statues' mouths is a passageway leading to another chamber. One of these leads to the Well of Souls, while another one leads to the entrance and exit of Abaddon. Where the other two lead to is currently unknown.
Well of Souls[]
The Well of Souls is an enormous circular chamber with a single stone bridge spanning across it. Beneath the bridge is an actual well of souls, composed of soul energy and bits and pieces of souls which are so incredibly old that they have begun to break down and disintegrate. It is connected to the City of the Damned and the Hall of Titans.
Abaddon during The Fall of Gods[]
Inbetween The Fall of Gods 1 and 2[]
Six years after the first chapter, the soul of Bardarus Bismarck was purged from his body and was trapped within the body of an owl. He was then imprisoned in the lowest chambers within Abaddon by Dacarus Bartolt's men.
During The Fall of Gods 2[]
Dugal Cain, Snowflake Booth, Melody Booth, Sebastian Fedorov, Karl Bachmeier, and Milus entered Abaddon together with Bardarus Bismarck to find the latter's lost Will of Peter, which was presumably hidden somewhere within the lower chambers according to intelligence gathered by the Rogue Inquisitors. They ran into a crazed Fillipo Moretti on the bridge spanning across the Well of Souls, who had apparantly been turned into a Neo-Human. Dugal fought him, and after a brief power struggle, the fight ended when Milus used his psychic powers to throw Fillipo off the bridge.
The heroes continued their journey until they ran into Geraldus and Marcus Palmer, two inquisitors who had gone missing fourteen years ago whilst searching for Fillipo. After recognizing the heroes, the two former inquisitors revealed that they had become Guardians in the service of the Keeper after having given up finding Fillipo. The Palmer brothers led the heroes into the City of the Damned and pointed them to where they could find the Keeper, who they assured could help them find the Will of Peter.
The Keeper welcomed the heroes with discontent. During the ensuing conversation, it was revealed that it was the Keeper who had locked Bardarus and the Will of Peter up within Abaddon, after Harold Montego had brought the two down there and had convinced the Keeper that the two had been trying to do something which was forbidden according to the laws of the Apostle's Wills. Apparantly the Keeper was unaware that the Will of Iscariot had given up its role as leader of the Apostle's Wills and that it had gone completely mad. After communing with Dugal's Will of Matthew, the Keeper was convinced. Furious at Iscariot's betrayal and lies the Keeper briefly lost his cool, but quickly recomposed himself. He proceeded to point the heroes in the right direction.
The heroes left the City of the Damned and entered the Beast Quarters, where they had to fight off numerous bands of beastmen. It didn't take long until they caught the attention of Nikolas Oborski, the leader of the beastmen. A greedy collector of Abaddon's hidden artifacts, Nikolas revealed that the Will of Peter was in his possession. Being ignored by the Will of Peter and recognizing Dugal's ancient sword, Nikolas offered to trade the two artifacts. Dugal lied that he was interested, and together the heroes and the beastmen made their way towards Nikolas's vault. While on their way, Nikolas revealed that he used to be a fellow experiment subject of Ansed Booth and Alexander Theosus before he and the other beastmen were thrown into Abaddon.
When they had reached the vault, Bardarus silently removed himself from the group to find a way in while Dugal stalled Nikolas by suddenly refusing to do the trade. The discussion turned into a brief fight which was quickly stopped when Bardarus emerged from the vault, reunited with the Will of Peter, and holding a book in his beak which seemed to be of great importance to Nikolas. Wishing to end the fight before people were going to die, Bardarus threatened to tear the book apart should Nikolas not leave the area together with his beastmen. Nikolas complied and left. While on their way back to the City of the Damned, Bardarus revealed that the book contained photos and writings from Nikolas's parents, which explained why the book was so important to him.
Meanwhile, Charles Bismarck accompanied by several of his justiciars were escorting Stirling Mortlock and Deanna Bergeson, both who had been accused of treason, to the City of the Damned when they ran into Fillipo on the bridge spanning across the Well of Souls. The two talked, and it was revealed that during his fight against Dugal, Dugal's soul-manipulating powers had managed to briefly lift the Neostigma's control over Fillipo's soul, allowing Fillipo a moment of mental clarity. Fillipo told Charles that he was waiting on Dugal to return so that he could thank him, after which Fillipo would kill himself before the Neostigma could restore its control over his soul. Charles offered Fillipo to convey his thanks to Dugal so that he wouldn't have to wait for him. Fillipo agreed, and as Charles and his group continued their way to the City of the Damned, Fillipo ended his own life.
The heroes finally ran into Charles in the Keeper's temple in the City of the Damned. Charles revealed to his father Bardarus that he wasn't truly his son: he believed that he was a foreign soul which had been given false memories and which had been put into Charles's body. Wishing to discover his true identity, Charles requested to join the heroes, who accepted his help and that of the group of justiciars who were with Charles, who had also decided to abandon Dacarus Bartolt. After Dugal revealed the soul of Bardarus to the prisoners Stirling and Deanna, they immediately kneeled down in front of their pope and pledged their support to the heroes as well. The entire group was then teleported by Karl to the outside world, London, but not before Dugal paid one last visit to the Keeper, asking him for his aid in the fight against Dacarus Bartolt. The Keeper instead advised Dugal to commune with his Will of Matthew, which Dugal did. However, the Will of Matthew was unwilling to grant Dugal more of its power at that time, leaving Dugal with nothing but anger and frustration.