Balzac was the baron of a town and the main antagonist of Sword of the Berserk: Guts' Rage.
In his Apostle form, Balzac became a chimeric dragon with his reddened human torso fused into a dragon-like head with beetle horns. The body was a mixture of various animals with a monstrous scaly face and a secondary face on the tongue. The torso was mammalian in nature with fish fins on the legs and a snake-headed tail. On each knee was a the head of a different animal: a panther on the right foreleg, a eagle on the right hind leg, a wolf on the left foreleg, and a fish on the left hind leg. Like with his strengthened form, Balzac used twin halberds as his weapons of choice.
Balzac was once a considerate man who cared for his people until the pressure of juggling his responsibilities as both a ruler and as a husband to his ill wife Annette eventually got to him, causing him to become a bloodthirsty dictator. Balzac also learned of the Mandragora plant that spawned in a village near the borders of his domain, managing to steal only part of its heart from its caretaker, Eriza, to use in his research to develop a drug extract for his wife. While it saved Annette's life and stopped her body from aging, it ravaged her mind as a consequence. Regardless of the setback, using what fragment he had to infect his subjects into Mandragorans to experiment on, Balzac believed he could restore his wife's mind if he acquired the rest of the Mandragora Heart.
The chance arrived the day Guts came to his town with Puck and Casca, the baron requesting the swordsman's presence at his castle after learning he defeated a Mandragoran. After showing Guts the dungeon where he is keeping the infected, Balzac convinces the swordsman to accept his request with the hope that his research can cure Casca of her own mental illness. Even after Guts learns the truth about Balzac from the rebels, he continues the request regardless with Rita and some rebels accompanying him. But the Baron, having never intended to fulfill his end of the bargain, has Casca imprisoned while ordering his men to follow Guts and kill him once the heart is in his possession.
But complications arise when Casca, freed by Zodd while on a mission by Griffith, awakens the Mandragora heart fragment in Balzac's possession with all infected Mandragorans breaking free and running amok by the time Guts and Rita return. Guts fights his way to the castle to confront Balzac, who explains that neither of them will get what they want. Balzac also gives Rita his life story before he drinks a more potent extract of the Mandragora's Heart to fight Guts as a monstrous figure. Though mortally wounded by Guts, Balzac is given a new chance of life as Rita, thinking it was mere pendant belong to Eriza, unknowingly brought him his predestined Beherit. Balzac's blood activated the Beherit, offering the life of Annette as his sacrifice in order to be reborn as an Apostle before Guts kills him for good. Sometime after Guts leaves, the Skull Knight retrieves Balzac's beherit.
- Balzac possesses some similarity to Guts, both forced to commit horrible acts after the women they care for become shells of their former selves.