Isaac Gardner is a supporting character who serves as the strict and dedicated educator of Marguerit Farom. A man of serious and earnest disposition, he is a familiar figure at the estate, easily recognized by the eyepatch he wears over his right eye. He has brown hair and green eyes.

Isaac’s personality is defined by a powerful sense of responsibility, but it also carries a notable contradiction. He is a rigorous taskmaster who has trained Marguerit harshly, yet he feels a profound and personal guilt for her developing a curse disease, known as the curse disease, holding himself accountable for her condition. This guilt fuels his overprotective nature, which manifests most clearly in his disapproval of Marguerit getting close to the irresponsible and carefree Touka Scott, whose behavior Isaac finds unacceptable. His actions are largely motivated by a desire to protect Marguerit and ensure her well-being, even when his methods are extreme.

In the story, Isaac is primarily defined by his role as Marguerit’s guardian and teacher. After the collapse of Leland Tallman, he takes on the additional responsibility of becoming the head of the orphanage, striving to care for the children while continuing to support Marguerit’s ambitions to become an adventurer. He is also in charge of training the maids, and due to his strong character and leadership, he is respected by many people.

However, Isaac’s most crucial and secret role is that of one of the Four Great Necromancers, a group of powerful undead beings who have existed on the surface world for over a thousand years. This astonishing past is known to no one, placing him in the same hidden category as the King of Farom. This secret identity adds a deep layer of mystery to his otherwise straightforward persona as a strict but caring educator.

Isaac’s key relationships are centered on his ward. His entire world revolves around Marguerit Farom, whose growth he has devoted himself to passionately. His interactions with Touka Scott are largely negative, stemming from his belief that Touka is a bad influence on Marguerit. His character shows a degree of development as he transitions from being solely Marguerit’s personal educator to accepting the broader responsibility of running the orphanage. Though he remains worried about her, he ultimately sets aside his personal fears to cooperate with her desire to go on an adventure.

A notable and recurring aspect of Isaac’s character is his connection to the Farom-style Undressing Technique, a secret art known as Utsusemi. When this technique goes out of control, the result is that he ends up completely naked in public, a humiliating event that leads to him being confined multiple times as a consequence. Beyond this peculiar ability, his most formidable power is his hidden identity as a millennium-old necromancer, though the full extent of these abilities is not part of his daily life as an educator.