Brill: A former Arcanium squire summoned from the Twilight Temple by a ring given to him years earlier. Horatio reveals that he guided Brill under multiple identities and sends him to protect the Harbingers in Felonor.
Horatio Vinvestler: The true creator of the Arcanium and the architect of Brill's training. He admits that Brill's mentor and the Arcanium's supposed founder were identities he used while preparing Brill for a future role.
Whisper, also called Jack Valdemar: The lost prince of Felonor. Recovering his birth name reveals the Tangled One's ritual, the murder of his mother, and his transformation into a vessel for one of her children.
Ernan: Whisper's brother, whose fragmented memories also begin at sea. Mathias identifies him as the second vessel created for the Tangled One's twin children.
Mathias Ephelthine: An ancient wizard allied with the Tangled One. He reveals part of Whisper and Ernan's origin, proposes an alliance against Draxus Cale, and provides the anchor-marked ring meant for Horatio.
Lord Valdemar: Felonor's king and Whisper's biological father. He admits that fear and prosperity led him to surrender his son during the Festival of Drowning.
Normandy Borthal: Attempts to wield the Dark Scepter beneath Felonor. The artifact overwhelms him and forces him to attack Torin before the Harbingers knock him unconscious.
Bjorn: Takes the Dark Scepter from Normandy after it turns him against Torin. Bjorn resists the artifact's attempt to control him while the Harbingers escape the collapsing ruins.
The Tangled One: An ascended power worshipped through the Festival of Drowning. She transformed Jack Valdemar into a vessel, attacks Felonor through the sea and ghost ships, and seeks to reclaim Whisper and Ernan as her lost children.
Harbingers of Light: Recover a Crystallic fragment beneath Felonor, save Normandy from the Dark Scepter, and draw the Tangled One away from the flooded city before hearing Mathias's offer.
The Arcanium: A secret organization created by Horatio to study light, darkness, the plague, and other metaphysical forces. Brill was trained as one of its protectors.
The Siphon Order: Also called the Order of Siphers. An ancient group that included the Tangled One, Mathias, Horatio, Draxus Cale, and Zyltrix before its members became divided within Tyve.
The Vey: An ancient people connected to the ruins beneath Felonor and the Crystallic fragment recovered there.
Dredged: Ocean-born abominations associated with the Tangled One. Mathias claims that her earlier vessels survived for only a few years before degrading into Dredged.
Tentacled Guardian: A massive creature that reaches through the portal pool beneath Felonor. It attacks the Harbingers and destroys the chamber as they escape with the Crystallic fragment.
Ghost Ships: Spectral vessels that approach Felonor as the Tangled One raises the sea around the city. They recede after the Harbingers escape toward the Tear.
Brill's Ring: An Arcanium ring given to Brill at the beginning of his training. It activates when he is needed and transports him from the Twilight Temple to Horatio's tower.
Crystallic: A shattered artifact being reassembled by the Harbingers. The fragment beneath Felonor's palace brings the group to seven recovered pieces, with two still missing.
Dark Scepter: A profane artifact that overwhelms Normandy with images of hatred and forces him to attack Torin. Bjorn later takes it and resists its influence.
Anchor Ring: A ring created through the Tangled One's power and given to the Harbingers by Mathias. He instructs them to deliver it to Horatio if they accept his alliance.
Experimental Gliders: Unproven flying devices used by the Harbingers to escape Felonor and draw the Tangled One away from the city.
Simulacra: Artificial vessels created by the Tangled One in the likeness of her lost children. Mathias identifies Whisper and Ernan as unusually stable examples whose blood contains something ancient.
Divine Ascension: The process through which fear and worship transformed the Tangled One from a powerful being into a godlike power over Tyve's seas.
Ancient Blood: An unknown power within Whisper and Ernan that prevents them from degrading like the Tangled One's earlier vessels. Mathias claims that Draxus Cale also wants this power.
The Black Sun: The unnatural darkness beneath which Zyltrix allegedly abandoned the other members of the Siphon Order within Tyve.
Arcanium: Horatio's hidden tower near the Aurorius Falls. Brill is summoned there before being sent to Felonor.
Aurorius Falls: The region surrounding Horatio's Arcanium tower.
Felonor: The City of the Wolf and the kingdom ruled by Lord Valdemar. The Tangled One floods the city after Whisper learns that he is its lost prince.
Veyan Ruins beneath Felonor: Ancient chambers below the royal palace containing a portal pool and a fragment of the Crystallic.
Twilight Temple: The sanctuary from which Brill is transported when his Arcanium ring activates.
The Tear: The inactive portal where Mathias meets the Harbingers after their escape from Felonor.
Dios Ostium: A sealed passage Mathias wants to open after defeating Draxus Cale so that he and the Harbingers can reach the center of Tyve.
Festival of Drowning: Felonor's tradition of sacrificing young children to the Tangled One in exchange for safety and prosperity. Jack Valdemar was surrendered during the festival and transformed instead of being killed.
Transformation of Jack Valdemar: The Tangled One murders Jack's mother, uses the blood of rejected sacrifices, and remakes the child as a vessel for one of her lost sons. Jack survives as Whisper without remembering his original identity.
Fall of the Siphon Order: Mathias claims that the order entered Tyve seeking power before Zyltrix betrayed its members and left them trapped beneath the Black Sun.
