Undertaker is a Grim Reaper, who works as an informant to the Phantomhive family, since Vincent Phantomhive's time. He maintains a facade as a funeral director for normal society.
Undertaker is a lean man with long gray hair with a single braid, which is worn so as to hide his eyes. His eyes reflect the typical color of Grim Reaper eyes, a bright yellow green.
Undertaker has extensive black fingernails and a noticeable scar across his face, neck, and left pinky finger. His robe is predominantly black; additionally, his attire includes an incredibly lengthy top hat, and a gray scarf strapped across his chest and knotted by the hips. He wears an emerald ring on his left index finger.
"Do not judge others by their appearances..especially..not a retired grim reaper."
Before, when he did not hide his identity as a Grim Reaper, Undertaker wore square, silver-framed glasses, and a black trench coat. He did not have the scars across his neck and face, but still had his ear piercings.
Undertaker's Death Scythe is a silver, long and curving blade fastened at an angle with a miniature skeleton, whose skull is wrapped in spiky wires, to a wooden handle.
Personality
Known only by his profession, Undertaker is a mysterious man whose scarred face is never fully visible beneath his long hair and crooked top hat. He tends to punctuate his words with sweeping gestures and creepy giggles, and spends a considerable deal of time inside of coffins. He takes joy in frightening others, as he intentionally acts in a disconcerting manner to provoke a reaction. Undertaker frequently refers to the deceased as his "guests," and it is his hobby to remove organs from his "guests" for research.
"Want to dance with death?"
Undertaker has great and significant connections with the underworld society; as victims of murder from the underworld are often delivered to his place of business. Thus, he has voluminous knowledge in these macabre cases that allows him to be an informant. However, he does not exchange his services for "the Queen's money," as he dislikes Queen Victoria. Instead, he expects those that want information from him to amuse him in some way.
Undertaker is intrigued by humans, to the degree that he defied the Grim Reaper conduct out of his own volition so that he can manipulate the fundamental notions of life. He is exceptionally disenchanted by the aspect of death (which is considered to be the "end"); when one day he started asking the question : "What would happen if the end had a continuation?". For this question to be answered, he connects fake records to individuals' Cinematic Records. However, despite his many experiments, he could never successfully construct a soul, thus originating Bizarre Dolls, whom of which are nothing more than "flesh dolls without a self." Nonetheless, he is proud of his creation, and even when others remark on his deranged nature, he refuses to concede, and stresses the beauty of his Bizarre Dolls.
"Everything is so fantastic from this point of view..trust me. You do not see what i see."
Undertaker regards a particular chain of lockets as his "treasure." (On one locket, there is a date and a name engraved: 13 July 1866, Claudia P.) He eventually entrusts his treasure in Ciel Phantomhive's care.