When Undertaker disguises himself as the headmaster, he takes careful measures to conceal much of his face, particularly using a cylinder hat that hides a significant portion of his features. His attire is formal and sophisticated, in keeping with his assumed role. He dresses in a sleek black suit that provides a polished and professional appearance. Additionally, he wears white gloves, completing his headmaster persona with an elegant touch. This disguise is part of Undertaker’s ability to blend into various situations and maintain his mysterious, multi-faceted identity.

The headmaster, when disguised by Undertaker, is an enigmatic and elusive figure. His background and true intentions remain shrouded in mystery, contributing to his aura of intrigue. Despite his secretive nature, the headmaster commands great respect and authority within Weston College, and students dare not challenge his decisions or openly oppose his rules. His speech is minimal, and he prefers to remain silent, leaving others, such as Johann Agares, to speak on his behalf.

The headmaster’s exceptional physical abilities are noteworthy, with a speed and agility that rival even Sebastian Michaelis’. His reflexes are so sharp that he is often aware when someone, such as Sebastian, is pursuing him. These remarkable traits suggest something far beyond normal human capabilities, and it is later revealed that the headmaster is, in fact, Undertaker a Grim Reaper explaining his extraordinary abilities. However, it remains unclear whether these qualities were also present in the original headmaster before Undertaker assumed his guise.

In the Public School Arc, the headmaster of Weston College plays a mysterious role in the investigation of student disappearances. On June 4th, news spreads that the headmaster has attended the annual cricket tournament at the college. When Sebastian Michaelis attempts to pursue him, the headmaster eludes him with surprising ease, evading capture by skillfully maneuvering through the college grounds.

Sebastian realizes that the headmaster is intentionally avoiding him and decides to stop holding back, but when he grabs the headmaster’s coat, he finds that he has vanished. Later, the headmaster invites Ciel Phantomhive to a Midnight Tea Party, where Ciel expresses his concerns about the mysterious disappearances of several students, particularly Derrick Arden, whose sudden transfer and strange circumstances trouble him. Ciel requests the headmaster call Scotland Yard, but the headmaster remains silent, with Johann Agares speaking on his behalf, claiming all the missing students are accounted for, including Derrick.

To Ciel’s shock, Derrick suddenly attacks one of the other attendees, Herman, biting his arm, revealing that he is a Bizarre Doll—a creature Sebastian and Ciel previously encountered on the Campania. Sebastian quickly wraps Derrick in a tablecloth to subdue him and tends to Herman’s wound. Ciel reveals that Sebastian is his butler and that they are investigating the mystery of the missing students.

Ciel confronts the headmaster, pulling a revolver and demanding an explanation. The P4, a group of prefects, step forward and confess to having murdered Derrick and making a contract with the Aurora Society in a misguided attempt to protect the school. They claim the headmaster had no involvement. However, Sebastian interrupts, suggesting that the headmaster, who has been at the head of the table, was actually the one who orchestrated the entire incident. The headmaster then removes his hat, revealing himself to be none other than Undertaker.

Despite the revelation, Undertaker manages to escape, leaving behind a trail of confusion and unanswered questions.

In 1889, during Ciel Phantomhive’s infiltration of Weston College to investigate a series of disappearances, the real Headmaster is on a world tour and unavailable until fall. Undertaker, exploiting this absence, assumes the Headmaster’s identity to manipulate events within the school and further his mysterious plans.

As the de facto Headmaster, Undertaker wields control over the P4 and uses their loyalty to maintain his façade, ensuring that his actions go unquestioned by the student body and staff.

P4 (Perfect Four)
The Headmaster has a direct relationship with the P4, who act as his enforcers within Weston College. His appointments are considered prestigious and integral to the school’s governance.

Ciel Phantomhive
The usurped Headmaster (Undertaker) becomes a key obstacle in Ciel’s investigation, as his influence extends to the P4 and the entire structure of the school.

Undertaker
During the Headmaster’s absence, Undertaker’s impersonation of the Headmaster highlights his cunning and ability to manipulate influential positions for his own agenda.

The Headmaster of Weston College symbolizes the absolute power and tradition of one of England’s most prestigious schools. While the real Headmaster’s absence during the 1889 investigation creates a vacuum for manipulation, the authority and structure of the role remain pivotal to the school’s operation. The storyline involving Undertaker’s usurpation adds depth to the narrative, intertwining the school’s rigid hierarchy with the series’ overarching themes of intrigue and control.