Vis
The seventeen-year-old protagonist, secretly Diago, last surviving prince of the conquered island kingdom of Suus, who refuses to surrender his Will to the empire that killed his family. Adopted into Family Telimus as a covert spy, he climbs through the Catenan Academy, survives the Iudicium massacre, and ends the book triplicated across three parallel realities by the Labyrinth's Synchronization.
Ulciscor Telimus
A Military-faction senator who adopts Vis as a hidden weapon against Religion, sending him to the Academy to learn the truth about his brother Caeror's supposed suicide. He later threatens to hand Vis to the Sappers unless he runs the Labyrinth inside the forbidden western ruins.
Veridius Julii
The Academy's charming Principalis, who left Military for Religion immediately after Caeror's death and is Ulciscor's prime suspect. He claims to be working to prevent a second Cataclysm and begs the recovering Vis to take a Senate seat within Religion, a plea Vis refuses.
Relucia Telimus
Ulciscor's wife, secretly the senior Anguis figure Sedotia, the archer who recognized Vis during the Transvect ambush. She maneuvers him into serving the resistance and insists he win the Iudicium so the resulting Senate appointment places an Anguis agent inside the Republic's heart.
Callidus
A small, asthmatic, brilliant student whose father heads the Census, and the closest friend Vis makes at the Academy. Tortured by Anguis infiltrators during the Iudicium, he dies in Vis's arms after asking that his father be told why he was demoted, a dying request that determines Vis's final choice of faction.
Emissa
A senator's daughter in Class Three who volunteers for stable duty beside Vis and slowly becomes his love interest, sharing a first kiss with him in a sea cave on Suus. At the Iudicium's tower her eyes turn black; she stabs Vis and hurls him into the river, an attack Veridius attributes to her belief that the western ruins had tainted him.
Lanistia
Vis's blind tutor, formerly Caeror's lover, who lost both eyes in the incident that killed him and senses the world by keeping the air around her charged with Will. Among the deadliest fighters Vis has ever faced, she trains him savagely and protests when Ulciscor orders him into the western dome.
Eidhin
A refugee from conquered Cymr who starts as a Class Six bully and becomes Vis's roommate and friend once Vis begins speaking Cymr with him. The pair beat the training Labyrinth together, though he politely declines to join Vis's Iudicium team.
Estevan
Leader of the Anguis resistance and once an advisor to Vis's father on Suus. After using a Will-imbued stylus to slaughter thousands at the naumachia, he dies when Vis presses the stylus to his neck and he leans into it, leaving Vis celebrated as a national hero.
Caeror Telimus
Ulciscor's brother, presumed to have died by suicide during an Iudicium three years before the novel, whose coded letter about a gate and lost places sets the whole plot in motion. The epilogue reveals him alive in Obiteum, welcoming one of the three Vises to a parallel reality.
Aequa
Daughter of the Governance senator Advenius Claudius, sent to train alongside Vis and serving as his social cover in Caten. In the Iudicium she seems to turn on Vis before proving to be a double agent quietly wrecking the rival Iro's team from within.
Belli
A Class Three student whom Vis displaces through a carefully staged Foundation match, getting her demoted. She is later murdered, and Vis discovers her mutilated body inside the forbidden western dome.