Mark serves as Benno's indispensable assistant and right-hand man at the Gilberta Company, distinguished by short brown hair and his signature waistcoat over a white shirt. His demeanor exudes professionalism and dignity, marked by thoughtful precision in his work. Though generally kindhearted, Mark possesses a fiercely protective loyalty towards Benno, swiftly retaliating against any perceived disrespect. This bond traces back to their childhood; Mark joined Gilberta as an apprentice and remained steadfastly by Benno's side after his father's death, supporting his leadership. When Mark's own family sought to exploit this transition by undermining the company, he turned against them, orchestrating their store's ruin as retribution for their betrayal.

Mark first encounters Myne and Lutz when Benno summons him to assist them. He guides Myne through order forms and becomes Lutz's writing instructor and mentor, earning Lutz's deep respect as a role model. Committed to Lutz's growth, Mark pledges to hone him into someone capable of handling both Myne's unique demands and Benno's business. Intrigued by Myne's ability to calculate mentally, Mark requests she teach him this practical skill.

His expertise in information manipulation and strategic influence becomes crucial during the campaign to oust Hasse's mayor. Mark later transitions with Benno to the Plantin Company, continuing his vital support role. He further extends his mentorship by assisting Benno in educating his niece. Underpinning all his actions is Mark's personal aspiration: to serve as Benno's "God of Fire"—a metaphorical role embodying unwavering support from the shadows, enabling Benno's success and growth throughout their endeavors.