The Architects of Light. The Aether's Echo, #3

The journey to the center of the galaxy concludes in a revelation that reshapes the destiny of the human race. After surviving the "Shortcuts" of the void, the hollowed-out remains of the Pluto dock with World-3, a colossal megastructure orbiting a black hole and a stabilized yellow hypergiant. Here, the survivors meet the Aether-ancient, fluid beings of light who act as the "Librarians" of the universe, preserving species and memories against the encroachment of time.
In this "Garden of Gods, " the crew is healed of all physical ailments and offered a paradise of eternal safety. However, they soon learn that the Garden is under siege. A cosmic entropy known as "The Silence" or "The Eaters of Light" is consuming the galaxy, erasing stars and history alike. The Aether's golden shield is failing because their defense is too mathematically perfect; they require the "dissonance" and unpredictability of the human spirit to create a barrier the Silence cannot predict.
Faced with the "Partition, " the crew must make an irrevocable choice: accept "Ascension" to become immortal beings of light and join the Chorus that maintains the shield, or return to Earth with the "Blueprint"-a crystal containing the secrets to zero-point energy and cellular regeneration. Elias Thorne, merging fully with the station's interface, chooses to stay behind as an Architect, weaving human chaos-"Jazz"-into the cosmic song to hold back the dark.
Meanwhile, Commander Wei commands the reborn starship Orpheus on a one-way trip back to Sol, bringing the "fire" that will either save humanity or burn it down. Fifty years later, on a transformed and healed Earth, a signal returns from the Galactic Core, proving that the light still holds and the conversation between humanity and the stars has finally begun.