He was voiced by George Coe.
When his parents died, he and Lucilla received a large inheritance. As an adventurer, he and his sister found many rare items which he would later put in his museum. Lucilla died shortly after they arrived in Windhelm, and Calixto secretly started dabbling in necromancy hoping to bring her back from the dead.
Killing Spree and Investigation
Before the events of the game, he killed two women, one being Friga and used her home as a base. He is first seen at the crime seen of his third victim, Susanna the Wicked, where he plays the part of an innocent bystander. He claims he saw someone running off, but could not get a decent look.
The Dragonborn begins searching for clues and winds up finding a trail of blood leading to Hjerim, Friga's house and Calixto's base. The Dragonborn finds a strange amulet and is advised to ask Calixto to appraise it. He claims Wuunferth the Unliving owns it and used to practice necromancy before serving the jarl, before buying it off of the Dragonborn.
The Dragonborn presents the so-called evidence against Wuunferth to the jarl's steward and Wuunferth is promptly arrested. A few days later, Calixto kills his fourth victim, Arivanya. The Dragonborn visits Wuunferth in jail to find out where everything went wrong. Wuunferth explains that he has been noticing a pattern, and that the next murder will take place that very night, at the grey quarter.
The Dragonborn begins patrolling the grey quarter and immediately notices Calixto attempting to stab his fifth victim. If the Dragonborn stops him in time, his killing spree ends and the case is over. However, if he manages to kill his victim first, he will flee to Hjerim and become hostile, where the Dragonborn finally kills him and ends his murder spree.
Alternatively, the Dragonborn can confront Wuunferth directly instead of accusing him to the jarl's steward, preventing Wuunferth from being arrested resulting in the same discovery, before Arivanya is even killed.