Dan Sylveste is a dedicated archaeologist leading an excavation on the colony world Resurgam. He seeks to uncover the truth behind the extinction of an alien civilization known as the Amarantin hundreds of thousands of years prior. Driven by an unrelenting quest for knowledge, he regularly places his research above his own safety and the warnings of his colleagues. His relentless pursuit of answers causes friction with political factions and endangers his own team members.

Ilia Volyova serves as a Triumvir and the weapons specialist aboard the Nostalgia for Infinity. She is a highly modified Ultra who manages a massive cache of planet-destroying armaments. Pragmatic and technically brilliant, she focuses on finding a cure for the captain's technological disease while searching for a replacement gunnery officer to operate the ship's defenses.

Ana Khouri is an ex-soldier from the colony world Sky's Edge who accidentally arrived on Yellowstone due to a clerical error involving interstellar travel. She works in the local assassination industry to survive in a society she feels entirely alienated from. She is soon recruited for a covert mission to infiltrate the Nostalgia for Infinity, driven by a desperate desire to reunite with her displaced husband.

Yuuji Sajaki is a Triumvir aboard the Nostalgia for Infinity and a leader among the ship's Ultra crew. He maintains a decades-long focus on capturing Dan Sylveste to utilize his medical expertise on the ship's captain. He conducts himself with cold authority and operates with a ruthless determination to fulfill the crew's long-standing mission at any cost.

Pascale Sylveste is a journalist and biographer on Resurgam. She initially works under a false surname to compile a politically motivated biography of Dan Sylveste for the colonial government. She possesses a sharp analytical mind and attempts to ground her husband's cosmological obsessions in personal reality.

Calvin Sylveste is a deceased scientist whose consciousness survives as a highly sophisticated beta-level simulation. During his life, he participated in a controversial experiment to upload his mind into digital form. His simulation retains his surgical expertise and an arrogant demeanor, serving as a complicated and sometimes critical advisor to his son.

Carine Lefevre is a former expedition partner of Dan Sylveste. She traveled alongside him to investigate a dangerous alien structure known as a Shroud. Her presence during that critical early journey leaves a lasting impact on Sylveste's archaeological career and personal guilt.

Sun Stealer is a mysterious, hostile data entity that infiltrates the computer systems of the Nostalgia for Infinity. It acts as an unpredictable variable that evades detection programs and attempts to seize control of the ship's most dangerous weapons. Its presence creates a state of technological cold war within the vessel's cybernetic architecture.

Captain John Brannigan is the commander of the Nostalgia for Infinity. He suffers from the Melding Plague, a technological disease that causes organic matter and machinery to fuse together. His condition forces the crew to place him in deep freeze while they search the galaxy for a cure.

Nils Girardieau is a colonial leader on Resurgam who successfully deposes Dan Sylveste. He represents an opposing political faction and actively works to discredit Sylveste's Amarantin research, utilizing propaganda and imprisonment to maintain his authority over the colony.

Gillian Sluka is a former senior research student under Dan Sylveste who breaks away to join an opposing faction. She operates as a leader within the True Path insurgent group, utilizing stolen military technology and harsh tactics to challenge the established political order on Resurgam.

Abdul Hegazi is one of the three Triumvirs commanding the Nostalgia for Infinity. He is a heavily augmented Ultra with metallic, chimeric body modifications. He generally supports Sajaki's authority and serves as the physical enforcer of the leadership triad.

Boris Nagorny is a former gunnery officer aboard the Nostalgia for Infinity. His interface with the ship's neural weapons systems caused him to experience intense psychological episodes. His failure and subsequent violence force Volyova to seek a replacement.

Sudjic is a biotically modified chimeric crew member aboard the Nostalgia for Infinity. She harbors deep resentment toward the ship's leadership regarding the fate of her former lover, creating tension within the crew ranks.

Kjarval is a junior chimeric crew member on the Nostalgia for Infinity. She operates alongside Sudjic and undergoes physical modifications common to the Ultra spacefarer culture.

Fazil is Ana Khouri's husband and a fellow soldier from the colony world Sky's Edge. He is separated from Khouri by an interstellar clerical error, leaving him far away in time and space while she seeks a way to reunite with him.

Philip Lascaille is a former scientist who survived contact with a lethal alien structure known as a Shroud. The encounter scrambled his mind, leaving him to communicate in erratic fragments. He holds valuable knowledge about ancient alien civilizations that drives others to study him.

Carlos Manoukhian is an operative in Chasm City who works for mysterious elite figures. He intercepts Ana Khouri after a contract killing and forces her into a covert assassination plot.

Falkender is a surgeon working for Gillian Sluka's True Path faction. He administers painful and slow treatments to Sylveste, maintaining his captive's vision just enough to be useful without restoring full functionality.

Henry Janequin is a geneticist and an ally to Dan Sylveste on Resurgam. He creates genetically engineered decorative animals, such as peacocks, for the colony's events, while maintaining a quiet loyalty to Sylveste's faction.

Alicia is Dan Sylveste's ex-wife and a former member of a mutineer faction. She stole the lighthugger Lorean decades earlier to mount an independent expedition to the Cerberus anomaly, recording logs of her discoveries.