21 Spiral of Chronos

Since deploying Liv’s Empyrea frame, Babylonia has been developing another specialized frame for Lee that carries the Omega Weapon. Named Hyperreal, the frame provides complete immunity to the Punishing Virus without damaging the user’s M.I.N.D. In addition, it can enter a supercomputing state where Lee can deduce every possibility in the battle and utilize recorded data of his past attacks, simulating space-time manipulation.

During a mission, Lee has a premonition that leads to him discovering a set of coordinates encrypted in a familiar cipher—a secret code he and Murray used to communicate with each other in the past. The coordinates reveal the location of Shome’s hidden research. Shome’s recording claims that his goal is to reach the origin of knowledge by decrypting the virus’ language—its “code”—and mentions an Agent nicknamed “the Merciful One.” The content of the research allows Babylonian researchers to begin decoding the information contained within the Hetero-Shard Bianca recovered during the battle of Copperfield Aquarium.

However, Lee keeps the other half of the data hidden from Babylonia; it shows Murray conspiring with a mysterious figure who also wants information on “the Merciful One.” The revelation that Murray has connections to Babylonia’s enemies—including the Ascendants—makes Lee realize that even though they love each other, the brothers have grown estranged since he became a Construct.

During a combat simulation using the new frame, Lee experiences visions of his past and future alongside that of a tower he has never seen before. As Lee and Asimov discuss the possible causes behind those visions, Murray enters the room. Lee takes the opportunity to confront his brother.

Lee questions Murray on his dealings with the Ascendants and calls him out on his interference with the development of specialized frames, which led Liv to become the experimental subject of the Empyrea frame over Lee. Murray responds that everything he does is for Lee’s sake—he does not want to remain helpless while his brother continues to sacrifice himself. Since he learned the extent of the sacrifice his brother made to save him as a child, Murray has been doing everything in his power to ensure a happy life for Lee, even if it means making deals with dangerous individuals and putting himself in danger.

An emergency alert interrupts their conversation. A crimson tower, dubbed the “Hetero-Tower,” appears on Earth. It begins emitting electromagnetic signals powerful enough to reach Babylonia, disrupting both the human and Construct minds and causing them to turn against each other. Furthermore, the extreme virus concentration near the tower prevents regular Constructs from approaching it.

With the rest of Babylonia’s military paralyzed, the Hyperreal frame is humanity’s only chance to enter the tower and stop its signals. Since Hyperreal incorporates the Hetero-Shard’s data, he surmises that the quickest way to gain complete access to the frame would be to acquire the required information from the shard, so he stabs himself with it. The ability to decode the Punishing Virus’ language from the shard is the “gift” from the future version of Nanami, who observed all the potential wordlines, foresaw that humanity would need it to overcome the trial that awaits them, and transmitted the data to the past to help her friends. Having transferred to the new frame, Lee heads to the tower.

Meanwhile, Ishmael and Vonnegut observe the Hetero-Tower from Babylonia and Earth, respectively. Both imply that the tower’s appearance is a predetermined event—a test to gauge whether humanity can reach the higher dimension. Regardless of the result, Vonnegut predicts that it will have a significant impact on the Ascension Network.

As soon as Lee steps inside the Hetero-Tower, an influx of data overloads his M.I.N.D. The tower transcends the three-dimensional perception of time and exists as a space-time continuum. Combining this characteristic of the tower with the knowledge of the virus’ language, Lee can perceive the past and future of other worldlines.

Lee realizes this is not his first time entering the tower: he tried and failed to climb the tower in other myriad worlds, resulting in humanity’s doom. A hooded figure that assumes the form of a pink-haired woman appears before Lee. Describing herself as the arbiter of humanity’s potential, she beckons him to try one more time.

The amount of data and distress at witnessing countless doomed futures overwhelm Lee, but his love for the two individuals dearest to him—the Commandant and Murray—guides him. He revisits and interacts with moments in the past that become variables in the worldlines to change the tower’s structure and move forward. He also recognizes his faults as he looks back at the past: his tendency to hide his pain from others ended up hurting the ones he cherishes the most. Once a ruthless assassin who did not hesitate to sacrifice both others’ lives and his own to attain his goal–to save his brother–his experiences as a member of the Gray Ravens have taught him the importance of trusting his allies.

On the upper floors, Lee encounters his other selves from different worldlines. They remark that the Hyperreal frame does not exist in any other world, and thus, it may be the key to reaching the top.

Upon entering the combined M.I.N.D. of all versions of himself who arrived at the tower, Lee pieces together the truth. Through infinite trials and errors—by attempting to climb the tower and avert humanity’s doom in every possible world—the joint cognition of every “Lee” in the M.I.N.D. space deduced the way to save humanity.

However, tampering with the past before the tower’s emergence resulted in a greater tragedy. Therefore, “Lee” instead used the tower’s spacetime-transcending ability to nudge Hyperreal toward the solution by planting small hints in the past points of divergence. One example is the cipher that led him to Shome’s research and the hint regarding the virus’ language: it was neither Lee himself nor Murray who sent him a message using the code only the brothers knew, but “Lee” from the future. The visions of pasts and futures he had seen before he entered the tower were glimpses of his experiences in other worlds.

Lee from another world explains that he failed to save humanity and died in all other worldlines; every version of him except for Hyperreal exists only inside the tower as a M.I.N.D. projection. Each time he failed, one of his selves dragged the failed self into the M.I.N.D. space and killed him to prevent the butterfly effect.

Entrusting their memories and hopes to Hyperreal, Lee’s other selves encourage him to climb to the top of the tower, pass the trial that awaits him, and reprogram the rules of the tower to stop its electromagnetic signals.

Outside the tower, humanity’s situation has grown dire. Even the Gray Ravens Commandant, who was on a mission on the surface with Lucia and Liv when the tower emerged, begins to suffer the effects of its signals. In the meantime, Murray, one of the few people unaffected by the tower, commands Cerberus to keep the situation on Babylonia under control. He resolves to protect humanity and fight for the future to be with his brother in a peaceful world.

Lee reaches the threshold of the universe on the top of the tower. With the knowledge of all possible worlds, he attains a cognition of space-time that transcends the linearity of time. He hears the voice of the Observers—high-dimensional beings who monitor the development of civilizations. They consider the Hetero-Tower another height of evolution that emerged on Earth: humans and the virus use each other to grow in ways they could not have achieved on their own. For example, the Hetero-Creatures evolved into the Unidentified Twins by mimicking humans, and humanity created the Inver-Device and Constructs in response to the virus. Thus, the tower’s appearance is an evolutionary competition between the two. For humanity to triumph, they must overcome the threat of the virus represented by the Hetero-Tower.

The Observers’ goal is to find a future in which a mortal passes their trials and joins them in breaking a set of “rules” that even high-dimensional beings are bound to. They produce a feminine humanoid projection that resembles Ishmael and the hooded figure Lee encountered at the tower's entrance to test him in combat.

Lee draws upon the data of his encounter with the projection in other worldlines to defeat it. Upon his victory, the Observers invite him to join them as a high-dimensional entity. At the same time, they warn him that he will lose all memories related to the tower and the ability to transcend time once he leaves without accepting their offer. Lee turns them down, saying he will choose his future with his loved ones. Taken aback by the response, the Observers give their blessing and disappear.

Lee finds himself in front of the tower’s core. With the hint from his other selves and the knowledge of the virus’ language, his last action before leaving is to overwrite the logic of the tower so that it will absorb and purify the Punishing Virus. It now acts like an enormous Omega Weapon, creating a large “Clean Zone” around it.

The Gray Ravens and other Babylonian squads give Lee a warm welcome as he emerges from the tower. He reciprocates their cordiality, unlike his previous aloof self. Although he has forgotten the events inside the tower, his experiences in this world and all the others have changed him.