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The Infinity Fortress is a fictional locale in the world of the GetBackers manga series, and the anime based upon it. Named as such in the English translation of the manga, it is known in Japanese as Mugenjou (無限城, literally "infinite fortress") it is also variously translated as the Limitless Fortress in ADV's English dub of the anime, and Maze City in Animax's.

Early history

The Infinity Fortress is a conglomeration of disused, condemned buildings that have, through chance or design, clustered together to form a self-contained habitat. Many smaller buildings surround its ground level, serving as the entrance to the fortress, while the core is formed of one especially tall tower that is said to have originally been planned to be a highly-advanced domicile, only to have construction abandoned mid-way. The remains came to be populated by beings from all walks of life, including one of the men responsible for its construction, Gensui Radou. The Fortress was soon subdivided into three specific tiers – Lower Town, the Beltline and the enigmatic Babylon City.

The Dark Age

Before VOLTS existed, Lower Town was in an era of anarchy. It was besieged by the Beltline inhabitants and few could oppose them. It was during this era that Ginji was found by Takeru Teshimine and later became Raitei during an invasion by the Beltline monsters, and marked the arrival of many of the future members of VOLTS. It was also during this period that Fuuga, led first by Saizou Toufuuin and later by Kazuki Fuuchoin, was the most powerful gang in Lower Town.

The Era of VOLTS

While it isn’t clear exactly how the VOLTS were formed, it is noted that the four Kings were awed by Ginji and gathered around him, some disbanding their previous gangs to follow him, such as the case of Kazuki and his gang Fuuga. Through Ginji and VOLTS, Lower Town was able to experience as close to peace as they could ever know while living in the Infinity Fortress.

However, this era came to a close when Ban came and fought with Ginji before taking him outside of the Infinity Fortress. With that, VOLTS began to slowly collapse, until only MakubeX remained. As MakubeX says, while speaking of his dream, “First Ginji leaves, then Kazuki and Shido follow, and the other guy too (meaning Masaki Kurusu). Everyone disappears, until finally I’m the only one left at Infinity Fortress”.

Lower Town

Lower Town is the lowest portion of the fortress, with several layers extending below ground level. It is populated by a vast number – accounts state various numbers from thousands to millions – of society’s disenfranchised and destitute, those who have come to Infinity Fortress because they have nowhere else to go. Consequently, with many clashing independent personalities populating it, Lower Town proved to be a chaotic place – a situation not improved by constant attacks from the inhabitants of the middle level, the Beltline, whose monstrous, murderous inhabitants terrorized Lower Town. From the mayhem, one particular gang named "Fuuga" (風雅 Fūga, the translation "Elegance" is used in the anime), led by Kazuki Fuuchouin, emerged to bring some semblance of control. Little was anyone in Lower Town aware, however, that they were all subject to the controlling whims of the mysterious entity known as the “God of Infinity Fortress,” which dwells within the highest level of the fortress, Babylon City, and controls all that goes on within it.

Constantly flooding the entirety of the fortress are bizarre electromagnetic waves under the control of the "God". These waves subtly manipulate and control the electrical brain impulses of the fortress’s inhabitants, thereby warping their perceptions of reality. Unaware of this external manipulation, the inhabitants of Lower Town live in a world that is partially physical, and partially a “virtual reality” shaped by this electromagnetic radiation, seeing, hearing and reacting to sensations, things and even people who do not truly exist - living an existence that is fully malleable and subject to whatever desire the God of Infinity Fortress may choose to exert. Many inhabitants of the fortress possess incredible strength and super-normal physical abilities, and it is noted that wounds heal faster within its walls – at least of a portion of these unusual occurrences are a part of the fabricated virtual reality aspect of the fortress, but precisely how much is unclear.

When Takeru Teshimine came upon Ginji Amano, a young orphan boy apparently abandoned in the Infinity Fortress, he took him under his wing and raised him, keeping him safe in the midst of the chaos. As Ginji grew, his superhuman power to generate and control electricity began to manifest; this power allowed him to tap into the electromagnetic radiation, and with its additional energy, he became the inhumanly powerful “Lightning Emperor.” With his power, Ginji was able to establish the VOLTS – a gang led by him, and sub-commanded by the “four kings,” Kazuki Fuuchouin, Shido Fuyuki, Masaki Kurusu and the mysterious boy, MakubeX – and bring some measure of peace to Lower Town.

It would later be noted that Ginji’s electric abilities had subconsciously allowed him to manipulate the electromagnetic waves, and hence the virtual reality of the Infinity Fortress, shaping things to his desires – precisely how much this ability played into the VOLTS’ control of Lower Town is unknown.

The Beltline

Briefly mentioned in the anime and further fleshed out in the manga, the Beltline, the most dangerous area of the Infinity Fortress, is ruled by Der Kaiser, a mysterious man and Ban's father. The citizens of the Beltline are said to be immortal and imperishable, and they 'will rise back from the dead every time they are attacked'. In fact, the citizens of the Beltline are conceptual entities, which embodies the concept of void. Many residents of the Beltline have a hideous death-like appearance, but all of them possess frightening strength.

Within the Beltline are Logic Walls. Each Logic Wall separates a different dimension and reality from the next. There is a reality and dimension for each alternative choice. However, during the Get Back the Lost Time arc, because of the encroachment, the shifting, replacing, and erasing of realities made it difficult to locate such Logic Walls. Even Takeru Teshimine mentioned that he needed to be careful within the Beltline, because with just one step, he could find himself within a different dimension.

A unique feature of the Beltline is that the area is relatively unstable. As it exists between many worlds, virtual illusion and true reality are constantly in conflict with each other. One phenomenon is the existence of 'clones'. Because of multiple universes that exist, diverging from each possibility, clones exist. If a clone is accidentally killed, the real body also dies. The Beltline is also able to suck up one's life forces slowly, so that upon entering it, a person will feel very exhausted. However, in the Beltline, the movements of the cells are also greatly agitated, allowing quick healing.

Among the citizens of the Beltline are the Voodoo King, the Ura Fuuchouin triad, ex-VOLTS King Masaki Kurusu and his followers, Der Kaiser and Drei Ritter (who ruled a separate part) and uncounted undead.


The God of Infinity Fortress was revealed to be a secret cabal known as the “Brain Trust,” a group of powerful individuals – scientists, engineers, artists, politicians, patrons, and super-normal beings - that created the Infinity Fortress as an experimental site where any infinite number of ideas that could be conceived could be tested. Gensui Radou had been a member of the Brain Trust before discovering their true intent and leaving in disgust. Likewise, Masaki Kurusu was a Brain Trust operative who had been installed in Lower Town as a member of the VOLTS in order to observe their actions.

Continuing his plan to free Lower Town from the “God’s” control, MakubeX tapped into the “Archive,” the massive computer bank that controlled the virtual reality of the Infinity Fortress, and schemed to transfer the data that shaped Lower Town into his own computer system, thereby removing it from the God’s control. Aware of this plan, the Brain Trust ordered Kurusu to return to the fortress and abduct MakubeX in order to stop him. The news of his abduction reached the GetBackers, however, who defeated Kurusu and put their own plan into motion – with the help of Gensui Radou, they transferred Lower Town’s data into the computer banks of their associate, Paul Wan, and Ginji proceeded to destroy the Archive. With the Brain Trust’s copy of Lower Town’s data destroyed, it was finally freed from its control, fulfilling MakubeX’s desire.


In the "Get Back the Lost Time" arc, the final act of the manga, the GetBackers re-enter the Infinity Fortress with the intention of breaching the Babylon City, in order to save Himiko Kudo.

Also, the organization Brain Trust appears in the manga. Unlike its anime counterpart, the Trust is not using the Infinity Fortress as an experimental ground. In Volume 38, it is revealed that the Infinity Fortress, itself, is the culmination of the Brain Trust's plan - the assembly of all the world's qualia. Existence is nothing more than a tentative reality that each of us believes in, and qualia is the true essence of all things. The Infinity Fortress is the true essence of all things, as it is a system for the complete unification of the minds of all mankind. The Infinity Fortress is the origin of the creation.

There are different dimensions for the different routes in the forking branches in time. In other words, there is a different reality and dimension for every choice. With every choice, a route splinters in time, creating another dimension and reality (It seems that they were utilizing the many-worlds interpretation of quantum mechanics). The Archiver, which is the Guardian of Creation, contains all objects, all possibilities, and even chaos. Kyoji Kagami found a way to blur the dimensional boundaries, laying the groundwork for the Archive to be placed in an adjoining dimension. In other words, the Archive is the mind behind the Infinity Fortress, and the Infinity Fortress is all of creation.

Professor Amano mentioned that at first, the histories were aligned, but somewhere along the line, the histories began to diverge. The other world had become independent - a dark mirror of the original one, weaving its a history all on its own. The world of GetBackers operated on rules that were different from the original one. Things that were impossible in one world, happen like daily events in another.

At the end of the series, the Archive had erased all realities of all splintering dimensions from all possibilities, leaving nothing left. Ginji recreated all of existence from his memories, recreating the world that he remembered, including the Infinity Fortress.


  • Although it was never explained, Professor Amano feared that the Archive would erase her world, after it became independent. The Archive did in fact become independent, and since it had erased all dimensions, there would be nothing for Ginji to return back to. This meant that Ginji, who was floating in nothingness after his meeting with his mother, formed existence from his will, creating everything from a blank slate.
  • The Infinity Fortress is the origin of creation, meaning that although it existed within the world, it existed as its essence as well. It was explained numerous times that it housed an infinite amount of energy, and that if it ever shut down (since Ginji could demand more than infinite energy), everything would end. Also, because the Infinity Fortress is existence itself, this explains why its histories and destinies were able to affect reality outside of its walls, because it was the true essence of all things.
  • The Infinity fortress bears striking similarities to the real life Kowloon Walled City, which likely served as an inspiration.